When you twist your knee or fall on it, you can tear a stabilizing ligament that connects your thighbone to the shinbone. An anterior cruciate ligament (ACL) unravels like a braided rope when it's torn and does not heal on its own. Fortunately, reconstruction surgery can help many people recover their full function after an ACL tear.
Ligaments are tough, non-stretchable fibers that hold your bones together. The cruciate ligaments in your knee joints crisscross to give you stability on your feet. People often tear the ACL by changing direction rapidly, slowing down from running or landing from a jump. Young people (age 15-25) who participate in basketball and other sports that require pivoting are especially vulnerable. You might hear a popping noise when your ACL tears. Your knee gives out and soon begins to hurt and swell.
First treatment includes rest, ice compression and elevation (RICE) plus a brace to immobilize the knee, crutches and pain relievers. Get to your doctor right away to evaluate your condition.
Your doctor may conduct physical tests and take X-rays to determine the extent of damage to your ACL. Most of the time, you need reconstruction surgery. Your doctor replaces the damaged ACL with strong, healthy tissue taken from another area near your knee. A strip of tendon from under your kneecap (patellar tendon) or hamstring may be used. Your doctor threads the tissue through the inside of your knee joint and secures the ends to your thighbone and shinbone.
In a few cases when the ACL is torn cleanly from the bone it can be repaired. Less active people may be treated nonsurgically with a program of muscle strengthening.
Successful ACL reconstruction surgery tightens your knee and restores its stability. It also helps you avoid further injury and get back to playing sports. After ACL reconstruction, you'll need to do rehabilitation exercises to gradually return your knee to full flexibility and stability. Building strength in your thigh and calf muscles helps support the reconstructed structure. You may need to use a knee brace for awhile and will probably have to stay out of sports for about one year after the surgery.
Activities After a Knee Replacement
If you are a candidate for knee replacement surgery, you probably anticipate that life after the surgery will be much like life before it, only without the pain. In many ways, you are correct. But change doesn't happen overnight and your active participation in the healing process is necessary to ensure a successful outcome.
Although you will be able to resume most activities, you should avoid activities that place excessive stress on the new knee. The following suggestions will help you adapt to your new joint and resume your daily activities safely.
Activities in the hospital
The knee is the largest joint in the body, and replacing it is major surgery. Although you'll probably want to take it easy at first, early mobilization is important. If you had considerable pain in your knee, you probably cut back on your activities before surgery and your leg muscles may be weak. You'll need to build up strength in your quadriceps muscles to develop control of your new joint. Early activity is also important to counteract the effects of the anesthesia and to encourage healing. Your doctor and a physical therapist will give you specific instructions on wound care, pain control, diet and exercise.
Proper pain management is important in your early recovery. Although pain after surgery is quite variable and not entirely predictable, it can be controlled with medication. Initially, you will probably receive pain control medication through an intravenous (IV) connection so that you can regulate the amount of medication you need. Remember that it is easier to prevent pain than to control it. You don't have to worry about becoming dependent on the medication; after a day or two, injections or pills will replace the IV. You will also have to take antibiotics and blood-thinning medication to help prevent blood clots from forming in the veins of your thighs and calves.
You may lose your appetite and feel nauseous or constipated for a couple of days. These are normal reactions. You may be fitted with a urinary catheter during surgery and be given stool softeners or laxatives to ease the constipation caused by the pain medication after surgery. You will be taught to do breathing exercises to prevent congestion from developing in your chest and lungs.
Initially, you will have a bulky dressing around the knee and a drain to remove any fluid build up around the knee. The drain will be removed in a day or two. You may also be wearing elastic hose and, possibly, compression stocking sleeves. These plastic sleeves are connected to a machine that circulates air around your legs to help keep blood flowing normally.
Usually a physical therapist will visit you on the day after your surgery and begin teaching you how to use your new knee. You may be fitted with a continuous passive motion (CPM) machine that will slowly and smoothly straighten and bend your knee. Even as you lie in bed, you can "pedal" your feet and "pump" your ankles on a regular basis to promote blood flow in your legs.
Your hospital stay may last from 3 to 7 days, depending on how well you heal after surgery. Before you go home, you will need to meet several goals:
- 1. Get in and out of bed by yourself
- 2. Bend your knee approximately 90 degrees, or show good progress in bending your knee
- 3. Extend (straighten) your knee fully
- 4. Walk with crutches or a walker on a level surface and to climb up and down 2 or 3 stairs
- 5. Do the prescribed home exercises
You may experience mild swelling in your leg after you are discharged. Elevating the leg, wearing compression hose and applying an ice pack for 15 to 20 minutes at a time will help reduce the swelling. You may be permitted to take the CPM machine home with you for a few weeks, but this is not a substitute for the prescribed exercises.
You will probably need some help at home for several weeks. If you do not have sufficient help at home, you may be temporarily transferred to a rehabilitation center. The following tips can make your homecoming more comfortable.
- Rearrange furniture so you can maneuver with a walker or crutches. You may temporarily change rooms (make the living room your bedroom, for example) to avoid using the stairs.
- Remove any throw or area rugs that could cause you to slip. Securely fasten electrical cords around the perimeter of the room.
- Install a shower chair, gripping bar and raised toilet in the bathroom.
- Use assistive devices such as a long-handled shoehorn, a long-handled sponge and a grabbing tool or reacher to avoid bending too far over.
Activities at home
General guidelines for wound care include:
- Keep the area clean and dry. A dressing will be applied in the hospital and should be changed as necessary. Ask for instructions on how to change the dressing before you leave the hospital.
- Do not shower or bathe until the sutures or staples are removed, usually a week to 10 days after surgery. Keep the wound clean and dry.
- Notify your doctor if the wound appears red or begins to drain.
- Take your temperature twice daily and notify your doctor if it exceeds 100.5°F.
- Swelling is normal for the first three to six months after surgery. Elevate your leg slightly and apply ice.
- Calf pain, chest pain or shortness of breath are signs of a possible blood clot. Notify your doctor immediately if you notice any of these symptoms.
Medication. Take all medications as directed. You will probably be given a blood thinner to prevent clots from forming in the veins of your calf and thigh, because these clots can be life-threatening. If a blood clot forms and then breaks free, it could travel to your lungs, resulting in a pulmonary embolism, a potentially fatal condition.
Because you have an artificial joint, it is especially important to prevent any bacterial infections from settling in your joint implant. You should get a medical alert card and take antibiotics whenever there is the possibility of a bacterial infection, such as when you have dental work. Be sure to notify your dentist that you have a joint implant and let your doctor know if your dentist schedules an extraction, periodontal work, dental implant, or root canal work.
Diet. By the time you go home from the hospital, you should be eating a normal diet. Your physician may recommend that you take iron and vitamin C supplements. Continue to drink plenty of fluids and avoid excessive intake of vitamin K while you are taking the blood thinner medication. Foods rich in vitamin K include broccoli, cauliflower, Brussels sprouts, liver, green beans, garbanzo beans, lentils, soybeans, soybean oil, spinach, kale, lettuce, turnip greens, cabbage and onions. Try to limit your coffee intake and avoid alcohol. You should continue to watch your weight to avoid putting more stress on the joint.
Resuming normal activities: Once you get home, you should continue to stay active. The key is to remember not to overdo it! While you can expect some good days and some bad days, you should notice a gradual improvement and a gradual increase in your endurance over the next 6 to 12 months. The following guidelines are generally applicable, but the final answer on each of these issues should come from your doctor.
Physical therapy exercises: Continue to do the exercises prescribed for at least two months after surgery. Riding a stationary bicycle can help maintain muscle tone and keep your knee flexible. Try to achieve the maximum degree of bending and extension possible.
Driving: If your left knee was replaced and you have an automatic transmission, you may be able to begin driving in a week or so, provided you are no longer taking narcotic pain medication. If your right knee was replaced, avoid driving for 6 to 8 weeks. Remember that your reflexes may not be as sharp as before your surgery.
Airport metal detectors: The sensitivity of metal detectors varies and it is unlikely that your prosthesis will cause an alarm. You should carry a medic alert card indicating you have an artificial joint, just in case.
Sexual relations can be safely resumed approximately 4 to 6 weeks after surgery.
Sleeping positions: You can safely sleep on your back, on either side, or on your stomach.
Return to work: Depending on the type of activities you perform, it may be 6 to 8 weeks before you return to work.
Other activities: Walk as much as you like, but remember that walking is no substitute for the exercises your doctor and physical therapist will prescribe. Swimming is also recommended; you can begin as soon as the sutures have been removed and the wound is healed, approximately 6 to 8 weeks after surgery. Acceptable activities include dancing, golfing (with spikeless shoes and a cart), and bicycling (on level surfaces). Avoid activities that put stress on the knee. These activities include: tennis, badminton, contact sports (football, baseball), squash or racquetball, jumping, squats, skiing or jogging. Do not do any heavy lifting (more than 40 pounds) or weight lifting.
These exercises will help strengthen the quadriceps muscles on the front of the thigh that stabilize and move the knee.
1. Lie on your back with your arms at your side and your legs straight, together, and flat. Place a rolled towel or small pillow under your ankles to raise your heel slightly. Tighten the muscles on the top of one thigh as you push the back of your knee down toward the floor (bed). Hold for 5 seconds, relax for 5 seconds. Do 10 cycles with each leg.
2. Put a rolled blanket or pillow under your knee so that the knee bends about 30 to 40 degrees. Tighten the muscles on the top of your thigh and straighten the knee by lifting your heel off the floor (bed). Hold 5 seconds, then slowly lower your heel to the floor (bed). Repeat 10 to 20 times.
Adolescent Anterior Knee Pain
A teenager who is active in sports and starts to feel a dull, aching pain behind the kneecap (patella) on either or both legs may need to adjust his or her training routine. Chronic pain in the front and center of the knee (anterior knee pain) is common among active, healthy young athletes-especially girls. It does not mean that you will damage your knee by continuing to do activities. You will just hurt more. If you get treatment for pain behind the kneecap, it usually gets better without surgery. Pain below the kneecap (on the upper shin) is a different problem not discussed here.
To help your physician with making the diagnosis, tell him or her when your knee pain started and provide details about your sports participation and training. Were there any recent changes to the duration, frequency or intensity of your activities? Any alterations in your equipment or the surfaces you play upon? Tell the doctor exactly which activities aggravate your knee pain. A standard knee exam will help your doctor determine the cause of pain behind your kneecap and rule out other problems. He or she may ask you to stand, walk, jump, squat, sit and lie down. It's important to relax! Your doctor may check:
- Alignment of the lower leg, kneecap and quadriceps.
- Knee stability, hip rotation and range of motion of knees and hips.
- Under the kneecap for signs of tenderness.
- The attachment of thigh muscles to the kneecap.
- Strength, flexibility, firmness, tone and circumference of thigh and hamstring muscles.
- Tightness of the heel cord and flexibility of the feet.
- Both of your legs may be X-rayed.
Risk Factors / Prevention
The complex anatomy of the knee joint that allows it to bend while supporting heavy loads is extremely sensitive to small problems in alignment, training and overuse. Pressure may pull the kneecap sideways out of its groove, causing pain behind the kneecap. In teenagers, a number of factors may be involved:
- Inflexibility of thigh muscles that support the knee joint.
- Knock-knees or abnormal hip rotation.
- Using improper sports training techniques or equipment.
- Overdoing sports activities.
A direct blow can also cause pain behind the kneecap. See your doctor to diagnose the cause of pain behind your kneecap and get treatment.
You may be able to prevent recurrences of pain behind the kneecap. Recommendations include:
- Wear shoes appropriate to your activities.
- Warm up with stretching exercises before physical activity.
- Stop doing any activity that hurts your knees.
- Limit the total number of miles you run in training and competition.
The pain usually begins gradually. You might hear popping or crackling sounds in the knee when you climb stairs or stand up and walk after prolonged sitting. Pain might flare up when you do activities that repeatedly bend the knee (i.e., jumping, squatting, running and other exercise) and at night. Without treatment, you may also develop thigh muscle (quadriceps) weakness. Your knees could begin to buckle or give way from pain.
Ice, rest and rehabilitation are the usual treatments for teenagers with pain behind the kneecap. Non-steroidal anti-inflammatory medicines (NSAIDs) like ibuprofen may also help particularly painful episodes.
Ice: To relieve swelling and inflammation, apply ice wrapped in a towel to your sore knee a few times a day.
Rest: Until the tissues heal, stop doing the activities that make your knee hurt. This probably means changing your training routine. You might need to learn proper exercise techniques. If you are obese, your doctor may recommend that you lose weight to reduce pressure on the knee. You may also benefit from using a simple knee sleeve with the kneecap cut out. Strap or support devices (i.e., braces, shoe orthoses) may also help.
Rehabilitation: After the pain and swelling go down, you will probably need to rehabilitate your knee to regain range of motion, strength, power, endurance, speed, agility and coordination. Your doctor may prescribe an exercise program to normalize your thigh muscle and hamstring flexibility and strength, or recommend cross-training activities that emphasize stretching of the lower extremities (i.e., water aerobics, bike riding). Resume running and other sports activities gradually.
NSAIDs: Use as needed for pain. Occasionally, three times a day dosing for several days can also help if pain doesn't go away.
Arthritis of the Knee
Three basic types of arthritis may affect the knee joint.
1. Osteoarthritis (OA) is the most common form of knee arthritis. OA is usually a slowly progressive degenerative disease in which the joint cartilage gradually wears away. It most often affects middle-aged and older people.
2. Rheumatoid arthritis (RA) is an inflammatory type of arthritis that can destroy the joint cartilage. RA can occur at any age. RA generally affects both knees.
3. Post-traumatic arthritis can develop after an injury to the knee. This type of arthritis is similar to osteoarthritis and may develop years after a fracture, ligament injury or meniscus tear.
Symptoms of arthritis
Generally, the pain associated with arthritis develops gradually, although sudden onset is also possible. The joint may become stiff and swollen, making it difficult to bend or straighten the knee. Pain and swelling are worse in the morning or after a period of inactivity. Pain may also increase after activities such as walking, stair climbing or kneeling. The pain may often cause a feeling of weakness in the knee, resulting in a "locking" or "buckling." Many people report that changes in the weather also affect the degree of pain from arthritis.
Making the diagnosis
Your doctor will perform a physical examination that focuses on your walk, the range of motion in the limb, and joint swelling or tenderness. X-rays typically show a loss of joint space in the affected knee. Blood and other special imaging tests such as an MRI may be needed to diagnose RA.
In its early stages, arthritis of the knee is treated with conservative, nonsurgical measures.
- Lifestyle modifications can include losing weight, switching from running or jumping exercises to swimming or cycling, and minimizing activities such as climbing stairs that aggravate the condition.
- Exercises can help increase range of motion and flexibility as well as help strengthen the muscles in the leg.
- Using supportive devices such as a cane, wearing energy-absorbing shoes or inserts, or wearing a brace or knee sleeve can be helpful.
Other measures may include applications of heat or ice, water exercises, liniments or elastic bandages.
- Several types of drugs can be used in treating arthritis of the knee. Because every patient is different, and because not all people respond the same to medications, your orthopaedic surgeon will develop a program for your specific condition.
- Anti-inflammatory medications can include aspirin, acetaminophen or ibuprofen to help reduce swelling in the joint.
- Glucosamine and chondroitin (kon-dro'-i-tin) sulfate are oral supplements may relieve the pain of osteoarthritis.
- Corticosteroids are powerful anti-inflammatory agents that can be injected into the joint.
- Hyaluronate (hi-a-lou'-ron-ate) therapy consists of a series of injections designed to change the character of the joint fluid.
- Special medical treatments for RA include gold salt injections and other disease-modifying drugs.
If your arthritis does not respond to these nonoperative treatments, you may need to have surgery.
- Arthroscopic surgery uses fiber optic technology to enable the surgeon to see inside the joint and clean it of debris or repair torn cartilage.
- An osteotomy cuts the shinbone (tibia) or the thighbone (femur) to improve the alignment of the knee joint.
- A total or partial knee arthroplasty replaces the severely damaged knee joint cartilage with metal and plastic.
- Cartilage grafting is possible for some knees with limited or contained cartilage loss from trauma or arthritis.
Orthopaedic surgeons are continuing to search for new ways to treat arthritis of the knee. Current research is focusing on new drugs as well as on cartilage transplants and other ways to help slow the progress of arthritis.
Care of the Aging Knee
Many people in the "baby boomer" generation are staying active as they age. This is healthy. But playing team sports, jogging or doing other high impact activities that repeatedly pound, twist and turn the knees can stress aging joints. Highly active, middle-aged patients may develop painful knees as a result of osteoarthritis (OA). This painful condition happens when the cartilage lining on the ends of bones gradually wears away. It can affect one or both knees.
Symptoms: You may experience pain when standing or going up and down stairs. The knee may buckle and give way, lock in place, or become stiff and swollen.
Patients: Most people with OA of the knee are over age 55 and/or obese and/or have a family history of OA. Younger, highly active people may also develop OA if their knee suffered a significant injury.
Diagnosis: See your doctor for diagnosis and treatment. The doctor will consider your comprehensive medical history, perform a physical examination and possibly order tests and/or imaging studies before recommending a course of treatment.
Extending the life of the middle-aged knee
Increasingly, baby boomers with OA of the knee are asking for total knee replacement surgery. But first they should try making changes to their lifestyles. Mayo Clinic orthopaedic surgeon Arlen D. Hanssen, MD presented a briefing on "Our Aging Population" at the 2002 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS). He said many highly active patients in their 40s and 50s feel inspired by advertising and news reports about the success of knee replacement surgeries. But often they refuse to change their lifestyles to extend the life of their natural knees.
"They come in and say, -fix me,'" Dr. Hanssen explained, and they hope for a complete end to their symptoms without making any changes in their activities. In reality, doctors use a complex medical process to determine whether total knee replacement is appropriate for a patient - considering age, activity demands and other factors. Long-term results of joint replacement are less certain in younger patients.
For middle-aged people, the earlier a doctor diagnoses OA of the knee, the more likely conservative treatment may help. If OA of the knee is in its early stages, your doctor may recommend low impact activities and other non-operative treatments that can delay or eliminate the need for surgery. In some cases, activity modification may be the only treatment a middle-aged patient needs. "In other cases when surgery is eventually needed, the patient still has to modify activities first to preserve the replacement joint," Hanssen advises.
Substitute smooth, low impact activities
Moderate physical activity lessens joint pain and improves flexibility and function. Baby boomer patients with OA of the knee should continue exercising, but change the forms of their activities:
- Stop doing high impact activities that twist and turn the joints. This includes running, tennis, racquetball, basketball, baseball, etc.
- Start doing smooth, low impact activities that are easier on the joints. Recommended activities include stretching, swimming, water aerobics, cycling, walking on a treadmill or outside, playing golf, etc.
Other conservative options
Other options that may extend the life of your natural knee include medications, steroid injections, physical therapy and mechanical aids.
Medications: The doctor may prescribe non-steroidal anti-inflammatory medications to help reduce inflammation. Certain dietary supplements may also help. Glucosamine stimulates formation and repair of articular cartilage, and chondroitin sulfate prevents cartilage from degrading. (Note: The U.S. Food and Drug Administration does not test dietary supplements. These compounds may cause negative interactions with other medications or excessive bleeding during surgery. Always consult your doctor before taking dietary supplements.)
Injections: The doctor may inject the knee joint with strong anti-inflammatory medications called corticosteroids. This can relieve pain and swelling for awhile.
Physical therapy: The doctor may give you a balanced fitness program including physical / occupational therapy to improve joint flexibility, increase range of motion, strengthen muscle, bone and cartilage tissues and reduce pain. It may also help to ice the affected joint for short periods, several times a day.
Mechanical aids: You may need supportive or assistive devices such as an elastic bandage, splint, brace, cane, crutches or walker.
Cemented and Cementless Knee Replacement
In a normal knee, four ligaments help hold the bones in place so that the joint works properly. When a knee becomes arthritic, these ligaments can become scarred or damaged. During knee replacement surgery, some of these ligaments, as well as the joint surfaces, are substituted or replaced by the new artificial prostheses. Two types of fixation are used to hold the prostheses in place. Cemented designs use a fast-curing bone cement (polymethylmethacrylate) to hold the prostheses in place. Cementless designs rely on bone growing into the surface of the implant for fixation.
The majority of knee replacements done today are cemented into place. Cemented knee replacements have a generally excellent track record and may last more than 20 years. The longevity and performance of a knee replacement depends on several factors, including activity level, weight and general health.
Cemented fixation relies on a stable interface between the prosthesis and the cement as well as a solid mechanical bond between the cement and the bone. Today's metal alloy components rarely break, but they can occasionally come loose from the bone. Two processes, one mechanical and one biological, can contribute to loosening.
1. During natural movement, the knee is subject to considerable loads and stresses, which the prostheses must transfer to the underlying bone. Because the hard subchondral bone of the shinbone (tibia) is removed during a knee replacement, loads are absorbed by the softer cancellous bone and the peripheral cortical bone that remains. If loads are heavier than the underlying bone can bear over a long period of time, the prosthesis will begin to sink into or loosen from its attachment to the bone. Additionally, if the load applied to the knee during walking is uneven, one side of the implant may "lift off" the bone as the other side is pressed into it, resulting in uneven wear of the polyethylene liner between the metal components. This wear creates debris particles of polyethylene that can trigger a biologic response and further contribute to loosening of the implant and sometimes to bone loss around the implant.
2. The microscopic debris particles are absorbed by cells around the joint and initiate an inflammatory response from the body, which tries to remove them. This inflammatory response can also cause cells to remove bits of bone around the implant, a condition called osteolysis. As wear continues, so does the bone loss. The bone weakens, and the loosening of the implant from bone increases. Despite these recognized failure mechanisms, the bond between cement and bone is generally very durable and reliable. Cemented TKA has been used successfully in all patient groups for whom total knee replacement is appropriate, including young and active patients with advanced degenerative joint disease.
In the 1980s, implant designs were introduced that were intended to attach directly to bone without the use of cement. These designs have a surface topography that is conducive to attracting new bone growth. Most are textured or coated so that the new bone actually grows into the surface of the implant. They may also use screws or pegs to stabilize the implant until bone ingrowth occurs. Because they depend on new bone growth for stability, cementless implants require a longer healing time than cemented replacements. Some cementless total knee designs have been as successful as cemented designs in relieving pain and restoring function.
However, cementless prostheses have not solved the problems of wear and bone loss. In all knee replacement designs, metal (usually a titanium- or cobalt/chromium-based alloy) rubs against ultrahigh-density polyethylene. Even though the metal is polished smooth and the polyethylene is treated to resist wear, the loads and stresses of daily movements will generate microscopic particulate debris. This debris, in turn, can trigger the inflammatory response that results in osteolysis.
Because cementless prostheses have not been used for as long as cemented prostheses, comparisons of long-term use is not possible. However, short-term outcome studies generally showed that cementless TKA has success rates comparable to cemented TKA.
In a hybrid TKA, the femoral component is inserted without cement, and the tibial component is inserted with cement. This technique was introduced in the early 1980s; long-term results are just now being measured and are generally positive.
Knee replacement operations, whether they use cemented or cementless fixation, are highly successful in relieving pain and restoring movement. However, the ongoing problems with wear and particulate debris may eventually necessitate further surgery, including replacing one or more parts of the knee replacement (revision surgery).
Deep Vein Thrombosis
Joint replacement surgery, especially in the lower extremities, is becoming more common. Orthopaedic surgeons performed about 364,000 hip replacements and about 451,000 knee replacements in 2003 (Source: National Center for Health Statistics; Centers for Disease Control and Prevention; 2003 National Hospital Discharge Survey.) The vast majority of these surgeries are very successful, and patients go on to live fuller, more active lives without pain. But no operation is without risks. One of the major risks facing patients who undergo orthopaedic surgery in the lower extremities is a complication called deep vein thrombosis, a form of venous thromboembolic disease.
What is it?
Deep vein thrombosis (DVT) refers to the formation of a thrombus (blood clot) within a deep vein, commonly in the thigh or calf. This can have two serious consequences:
1. If the thrombus partially or completely blocks the flow of blood through the vein, blood begins to pool and build-up below the site. Chronic swelling and pain may develop. The valves in the blood vessels may be damaged, leading to venous hypertension. A person's ability to live a full, active life may be impaired.
2. If the thrombus breaks free and travels through the veins, it can reach the lungs, where it is called a pulmonary embolism (PE). A pulmonary embolism is a potentially fatal condition that can kill within hours.
Both DVT and PE may be asymptomatic and difficult to detect. Thus, physicians focus on preventing their development by using mechanical or drug therapies. Without this preventive treatment, as many as 80 percent of orthopaedic surgical patients would develop DVT, and 10 percent to 20 percent would develop PE. Even with these preventative therapies, DVT and subsequent PE remain the most common cause for emergency readmission and death following joint replacement.
Although venous thromboembolic disease can develop after any major surgery, people who have orthopaedic surgery on the lower extremities are especially vulnerable. Three factors contribute to formation of clots in veins:
1. Stasis, or stagnant blood flow through veins. This increases the contact time between blood and vein wall irregularities. It also prevents naturally occurring anticoagulants from mixing in the blood. Prolonged bed rest or immobility promotes stasis.
2. Coagulation, which is encouraged by the presence of tissue debris, collagen or fats in the veins. Orthopaedic surgery often releases these materials into the blood system. During hip replacement surgery, reaming and preparing the bone to receive the prosthesis can also release chemical substances (antigens) that stimulate clot formation into the blood stream.
3. Damage to the vein walls, which can occur during surgery as the physician retracts, twists, folds or manipulates veins. This can also break intercellular bridges and release substances that promote blood clotting.
Other factors that may contribute to the formation of thrombi in the veins include: age, previous history of DVT or PE, metastatic malignancy, vein disease (such as varicose veins), smoking, estrogen usage or current pregnancy, obesity and genetic factors.
After hip surgery, thrombi often form in the veins of the thigh; these clots are more likely to lead to PE. After knee surgery, most thrombi occur in the calf; although less likely to lead to PE, these clots are more difficult to detect. Fewer than one third of patients with DVT present with the classic signs of calf discomfort, edema, distended veins, or foot pain.
Prevention is a three-pronged approach designed to address the issues of stasis and coagulation. Usually, several therapies are used in combination. For example, a patient may be fitted with graded compression elastic stockings and an external compression device upon admittance to the hospital; movement and rehabilitation begin the first day after surgery and continue for several months; anticoagulant therapy may begin the night before surgery and continue after the patient is discharged.
1. Early movement/rehabilitation: With hospital stays averaging just four to seven days after an arthroplasty on the lower extremity, early movement is imperative as well as beneficial. Physical therapy, including joint range of motion, gait training and isotonic/isometric exercises, usually begins on the first day after the operation. Pain relievers administered intravenously also facilitate early mobilization.
2. Mechanical prophylaxes: Mechanical preventatives are usually used in combination with other therapies. They include:
Lower extremity exercises such as simple leg lifts, elevating the foot of the bed, and active and passive ankle motion to increase blood flow through the femoral vein.
Graded compression elastic stockings, which are more effective in preventing thrombi formation in the calf than in the thigh.
Continuous passive motion, which is a logical treatment, but has not been proven effective in preventing the development of DVT.
External pneumatic compression devices that apply pulsing pressures similar to those that occur during normal walking. They can help reduce the overall rate of DVT occurrence when used with other therapies, but they are difficult to apply and patient compliance is often a problem.
In rare cases, a filter device may be inserted in the vein.
3. Pharmacologic prophylaxis: The use of anticoagulant pharmacologic agents includes an inherent risk of increased bleeding, which must be measured against their effectiveness in preventing clot formation. The most common anticoagulants are aspirin, warfarin and heparin.
Aspirin is easy to administer, is low cost, has few bleeding complications, and doesn't need to be monitored. However, it has not been proven more effective than other agents and may not be advisable for all patients. Studies have shown that aspirin has a greater protective effect for men than for women.
Warfarin is the most commonly used agent for hip and knee replacement patients. Warfarin interferes with vitamin K metabolism in the liver to prevent formation of certain clotting factors. Because warfarin takes at least 36 hours to start working, and four to five days to reach its maximum effectiveness, it is usually started the day before surgery. Low doses are used because higher doses can cause episodes of bleeding, but the dose response is difficult to predict and warfarin must be administered through an outpatient clinic. Warfarin can cause fetal damage.
Heparin is a naturally occurring substance that inhibits the clotting cascade. It can come in high (standard unfractionated heparin) or low (fractionated heparin) molecular weights. Recent emphasis has been on low molecular weight heparins (LMWH) because they are more predictable and effective, with fewer bleeding complications than standard unfractionated heparin. LMWH is effective after both hip and knee joint replacement surgeries, but there is a higher incidence of bleeding when it is used after knee replacement surgery. The most commonly used and researched LMWH are enoxaparin, ardeparin, dalteparin and fraxiparine. Heparin works much faster than warfarin, so it is often administered initially and followed by warfarin therapy, or administered as a single agent.
Diagnosing DVT is difficult, and current diagnostic techniques have both advantages and disadvantages. The most commonly used diagnostic tests include venography, duplex or Doppler ultrasonography, magnetic resonance imaging (MRI), and cuff-impedence plethysmography.
Venography uses a radiographic material injected into a vein on the top of the foot. The material mixes with blood and flows toward the heart. An X-ray of the leg and pelvis will then show the calf and thigh veins and reveal any blockages.
Although venography is very accurate and can detect blockages in both the thigh and the calf, it is also costly and cannot be repeated often. In addition, the injected material may actually contribute to the creation of thrombi.
Duplex ultrasonography can also be very accurate in identifying clogged veins. Projected sound waves bounce off structures in the leg and create images that reveal abnormalities. The addition of color Doppler imaging improves accuracy. This test is noninvasive and painless, requires no radiation, can be repeated regularly and can reveal other causes for symptoms. It also costs substantially less than venography. However, it is technically demanding and requires a skilled, experienced operator to obtain the most accurate results. Ultrasonography is less sensitive in detecting thrombi in the calf and it has limited ability to directly image the deep veins of the pelvis.
Magnetic resonance imaging is particularly effective in diagnosing DVT in the pelvis, and as effective as venography in diagnosing DVT in the thigh. This technique is being increasingly used because it is noninvasive and allows simultaneous visualization of both legs. However, an MRI is expensive, not always readily available, and cannot be used if the patient has certain implants, such as a pacemaker. In addition, the patient can experience claustrophobia.
Cuff-impedance plethysmography uses blood pressure checks at different places in the leg to identify possible blockages. Although once used extensively, this procedure is no longer recommended as a diagnostic tool because of its high false-positive rate.
The risk of developing DVT extends for at least three months after joint replacement surgery. The risk is greatest two to five days after surgery; a second peak development period occurs about 10 days after surgery, after most patients have been discharged from the hospital. Recently, the Food and Drug Administration approved the use of the LWMH dalteparin sodium in a once-daily, 14-day dosing regimen to prevent DVT after hip surgery. A common postoperative regimen is five days of heparin followed by three months of warfarin therapy. However, the length of time that therapy should continue after surgery varies depending on the agent used and individual patient considerations.
Orthopaedic surgeons are continuing to research techniques, such as the use of regional anesthesia and intraoperative heparin, to reduce the risk of DVT formation. Studies have shown that using regional rather than general anesthesia can reduce the overall rate of DVT formation by up to 50 percent.
Research to identify those patients particularly at risk for DVT formation after surgery is also ongoing. Some risk factors such as weight and history have been identified. Based on these risk factors, some physicians use regular surveillance of patients, while others recommend using venography to identify those patients at risk for developing DVT. In general, orthopaedic surgeons would rather avoid extended outpatient prophylaxis for all patients, preferring to focus on those most at risk.
Treatment is the same for both asymptomatic and symptomatic venous thrombo-embolisms. If the clot is located in the femoropoliteal vein of the thigh, treatment consists of bed rest and five days of heparin therapy followed by three months of warfarin. A clot in the calf veins does not normally require heparin treatment; outpatient warfarin treatment for six to 12 weeks is sufficient. These treatment regimens are designed to prevent the occurrence of a fatal pulmonary embolism and reduce the morbidity associated with DVT.
Goosefoot (Pes Anserine) Bursitis of the Knee
Pain and tenderness on the inside of your knee, just about two inches below the joint, are two of the symptoms of pes anserine bursitis of the knee. The pes anserine bursa is a small lubricating sac located between the shinbone (tibia) and three tendons of the hamstrings muscle at the inside of the knee. Because the three tendons splay out on the front of the shinbone and look like the foot of a goose, pes anserine bursitis is also known as "goose foot" bursitis.
Bursitis, an inflammation of a bursa, usually develops as the result of overuse or constant friction and stress on the bursa. Pes anserine bursitis is common in people with osteoarthritis of the knee. Athletes, particularly runners, are also susceptible. Several factors can contribute to the development of pes anserine bursitis, including:
- Incorrect training techniques, such as neglecting to stretch, doing excessive hill running and sudden increases in mileage.
- Tight hamstring muscles.
- An out-turning of the knee or lower leg.
- Osteoarthritis in the knee.
- Pain slowly develops on the inside of the knee and/or in the center of the shinbone, about two to three inches below the knee joint.
- Pain increases with exercise or climbing stairs.
- Symptoms may mimic those of a stress fracture, so an X-ray is usually required for diagnosis.
Athletes who have pes anserine bursitis should take steps to modify their workout program so that the inflammation does not recur. Other treatments include:
Rest. Discontinue the activity or substitute a different activity until the bursitis clears up.
Ice. Apply ice at regular intervals three or four times a day for 20 minutes at a time.
Anti-inflammatory medication. Aspirin or ibuprofen will ease the pain and reduce the inflammation.
Injection. Your doctor may inject a solution of anesthetic and steroid into the bursa. This often provides prompt relief.
If you have persistent pain, catching, or swelling in your knee, a procedure known as arthroscopy may help relieve these problems.
Arthroscopy allows an orthopaedic surgeon to diagnose and treat knee disorders by providing a clear view of the inside of the knee with small incisions, utilizing a pencil-sized instrument called an arthroscope. The scope contains optic fibers that transmit an image of your knee through a small camera to a television monitor. The TV image allows the surgeon to thoroughly examine the interior of your knee and determine the source of your problem. During the procedure, the surgeon also can insert surgical instruments through other small incisions in your knee to remove or repair damaged tissues.
Modern or contemporary arthroscopy of the knee was first performed in the late 1960s. With improvements of arthroscopes and higher-resolution cameras, the procedure has become highly effective for both the accurate diagnosis and proper treatment of knee problems. Today, arthroscopy is one of the most common orthopaedic procedures in the United States.
Whether you have just begun exploring treatment options for your problem knee or have already decided, with your orthopaedic surgeon, to have an arthroscopy, this booklet will help you understand more about this valuable procedure.
How the Normal Knee Works
The knee is the largest joint in the body, and one of the most easily injured. It is made up of the lower end of the thigh bone (femur), the upper end of the shin bone (tibia), and the knee cap (patella), which slides in a groove on the end of the femur. Four bands of tissue, the anterior and posterior cruciate ligaments, and the medial and lateral collateral ligaments connect the femur and the tibia and provide joint stability. Strong thigh muscles give the knee strength and mobility.
The surfaces where the femur, tibia and patella touch are covered with articular cartilage, a smooth substance that cushions the bones and enables them to glide freely. Semicircular rings of tough fibrous-cartilage tissue called the lateral and medial menisci act as shock absorbers and stabilizers.
The bones of the knee are surrounded by a thin, smooth tissue capsule lined by a thin synovial membrane which releases a special fluid that lubricates the knee, reducing friction to nearly zero in a healthy knee.
Normally, all parts of the knee work together in harmony. But sports, work injuries, arthritis, or weakening of the tissues with age can cause wear and inflammation, resulting in pain and diminished knee function.
Arthroscopy can be used to diagnose and treat many of these problems:
- Torn meniscal cartilage.
- Loose fragments of bone or cartilage.
- Damaged joint surfaces or softening of the articular cartilage known as chondromalacia.
- Inflammation of the synovial membrane, such as rheumatoid or gouty arthritis.
- Abnormal alignment or instability of the kneecap.
- Torn ligaments including the anterior and posterior cruciate ligaments.
By providing a clear picture of the knee, arthroscopy can also help the orthopaedic surgeon decide whether other types of reconstructive surgery would be beneficial.
Is Arthroscopy for You?Your family physician can refer you to an orthopaedic surgeon for an evaluation to determine whether you could benefit from arthroscopy.
Signs that you may be a candidate for this procedure include swelling, persistent pain, catching, giving-way, and loss of confidence in your knee. When other treatments such as the regular use of medications, knee supports, and physical therapy have provided minimal or no improvement, you may benefit from arthroscopy.
Most arthroscopies are performed on patients between the ages of 20 and 60, but patients younger than 10 years and older than 80 years have benefited from the procedure.
The Orthopaedic Knee Evaluation
The orthopaedic knee evaluation consists of three components:
- A medical history, in which your orthopaedic surgeon gathers information about your general health and asks you about your symptoms.
- A physical examination to assess your knee motion and stability, muscle strength and overall leg alignment.
- X-rays to evaluate the bones of your knee. Your orthopaedic surgeon may also arrange for you to have an MRI to provide more information about the soft tissues of your knee. An MRI uses magnetic sound waves to create images. They are not X-rays. Blood tests may be obtained to determine if you have arthritis.
Your orthopaedic surgeon will review the results of your evaluation with you and discuss whether arthroscopy would be the best method to further diagnose and treat your knee problem. Other treatment options, such as medications or other surgical procedures also will be discussed and considered.
Your orthopaedic surgeon will explain the potential risks and complications of knee arthroscopy, including those related to the surgery itself and those that can occur after your surgery.
Preparing for Surgery
If you decide to have arthroscopy, you may be asked to have a complete physical with your family physician before surgery to assess your health and to rule out any conditions that could interfere with your surgery.
Before surgery, tell your orthopaedic surgeon about any medications that you are taking. You will be informed which medications you should stop taking before surgery.
Tests, such as blood samples or a cardiogram, may be ordered by your orthopaedic surgeon to help plan your procedure.
Your Arthroscopic Knee Surgery
Almost all arthroscopic knee surgery is done on an outpatient basis. Your hospital or surgery center will contact you about the specific details for your surgery, but usually you will be asked to arrive at the hospital an hour or two prior to your surgery. Do not eat or drink anything after midnight the night before your surgery.
After arrival, you will be evaluated by a member of the anesthesia team. Arthroscopy can be performed under local, regional, or general anesthesia. Local anesthesia numbs your knee, regional anesthesia numbs you below your waist, and general anesthesia puts you to sleep. The anesthesiologist will help you determine which would be the best for you.
If you have local or regional anesthesia, you may be able to watch the procedure on a TV screen, if you wish.
The orthopaedic surgeon will make a few small incisions in your knee. A sterile solution will be used to fill the knee joint and rinse away any cloudy fluid, providing a clear view of your knee.
The surgeon will then insert the arthroscope to properly diagnose your problem, using the TV image to guide the arthroscope. If surgical treatment is needed, the surgeon can use a variety of small surgical instruments (e.g., scissors, clamps, motorized shavers, or lasers) through another small incision. This part of the procedure usually lasts 45 minutes to 1 1/2 hours.
Common treatments with knee arthroscopy include:
- Removal or repair of torn meniscal cartilage.
- Reconstruction of a torn cruciate ligament.
- Trimming of torn pieces of articular cartilage.
- Removal of loose fragments of bone or cartilage.
- Removal of inflamed synovial tissue.
At the conclusion of your surgery, the surgeon may close your incisions with a suture or paper tape and cover them with a bandage.
You will be moved to the recovery room. Usually, you will be ready to go home in one or two hours. You should have someone with you to drive you home.
Your Recovery at Home
Recovery from knee arthroscopy is much faster than recovery from traditional open knee surgery. Still, it is important to follow your orthopaedic surgeon's instructions carefully after you return home. You should ask someone to check on you that evening.
Swelling Keep your leg elevated as much as possible for the first few days after surgery. Apply ice as recommended by your orthopaedic surgeon to relieve swelling and pain.
Dressing Care You will leave the hospital with a dressing covering your knee. You may remove the dressing the day after surgery. You may shower, but should avoid directing water at the incisions. Do not soak in a tub. Keep your incisions clean and dry.
Your orthopaedic surgeon will see you in the office a few days after surgery to check your progress, review the surgical findings, and begin your postoperative treatment program.
Bearing Weight After most arthroscopic surgeries, you can walk unassisted but your orthopaedic surgeon may advise you to use crutches, a cane, or a walker for a period of time after surgery. You can gradually put more weight on your leg as your discomfort subsides and you regain strength in your knee. Your surgeon may allow you to drive after a week.
Exercises to Strengthen Your Knee You should exercise your knee regularly for several weeks following surgery to strengthen the muscles of your leg and knee. A physical therapist may help you with your exercise program if your orthopaedic surgeon recommends specific exercises.
Medications Your orthopaedic surgeon may prescribe antibiotics to help prevent an infection and pain medication to help relieve discomfort following your surgery.
Complications Potential postoperative problems with knee arthroscopy include infection, blood clots, and an accumulation of blood in the knee. These occur infrequently and are minor and treatable.Warning Signs
Call your orthopaedic surgeon immediately if you experience any of the following:
- Persistent warmth or redness around the knee.
- Persistent or increased pain.
- Significant swelling in your knee.
- Increasing pain in your calf muscle.
- Shortness of breath or chest pain.
Reasonable Expectations After Arthroscopic Surgery
Although arthroscopy can be used to treat many problems, you may have some activity limitations even after recovery. The outcome of your surgery will often be determined by the degree of injury or damage found in your knee. For example, if you damage your knee from jogging and the smooth articular cushion of the weight-bearing portion of the knee has worn away completely, then full recovery may not be possible. You may be advised to find a low-impact alternative form of exercise. An intercollegiate or professional athlete often sustains the same injury as a weekend recreational athlete, but the potential for recovery may be improved by the over-development of knee muscles. Physical exercise and rehabilitation will play an important role in your final outcome. A formal physical therapy program also may add something to your final result.
A return to intense physical activity should only be done under the direction of your surgeon.
It is reasonable to expect that by six to eight weeks you should be able to engage in most of your former physical activities as long as they do not involve significant weight-bearing impact. Twisting maneuvers may have to be avoided for a longer time.
If your job involves heavy work, such as a construction laborer, you may require more time to return to your job than if you have a sedentary job.
Your orthopaedic surgeon is a medical doctor with extensive training in the diagnosis and nonsurgical and surgical treatment of the musculoskeletal system, including bones, joints, ligaments, tendons, muscles, and nerves.
Knee Arthroscopy Exercise Guide
Regular exercise to restore your knee mobility and strength is necessary. For the most part this can be carried out at home. Your orthopaedic surgeon may recommend that you exercise approximately 20 to 30 minutes two or three times a day. You also may be advised to engage in a walking program. Your orthopaedist may suggest some of the following exercises. The following guide can help you better understand your exercise or activity program that may be supervised by a therapist at the direction of your orthopaedic surgeon. As you increase the intensity of your exercise program, you may experience temporary set-backs. If your knee swells or hurts after a particular exercise activity, you should lessen or stop the activity until you feel better. You should Rest, Ice, Compress (with an elastic bandage), and Elevate your knee (R.I.C.E.). Contact your surgeon if the symptoms persist.
Initial Exercise Program
Hamstring Contraction, 10 Repetitions - No movement should occur in this exercise. Lie or sit with your knees bent to about 10 degrees. Pull your heel into the floor, tightening the muscles on the back of your thigh. Hold 5 seconds, then relax.Repeat 10 times.
Quadriceps Contraction, 10 Repetitions - Lie on stomach with a towel roll under the ankle of your operated knee. Push ankle down into the towel roll. Your leg should straighten as much as possible. Hold for 5 seconds. Relax. Repeat 10 times.
Straight Leg Raises, 10 Repetitions - Lie on your back, with uninvolved knee bent, straighten your involved knee. Slowly lift about 6 inches and hold for 5 seconds. Continue lifting in 6-inch increments, hold each time. Reverse the procedure, and return to the starting position. Repeat 10 times. Advanced: Before starting, add weights to your ankle, starting with 1 pound of weight and building up to a maximum of 5 pounds of weight over 4 weeks.
Buttock Tucks, 10 Repetitions - While lying down on your back, tighten your buttock muscles. Hold tightly for 5 seconds. Repeat 10 times.
Straight Leg Raises, Standing, 10 Repetitions - Support yourself, if necessary, and slowly lift your leg forward keeping your knee straight. Return to the starting position. Repeat 10 times Advanced: Before starting, add weights to your ankle, starting with 1 pound of weight and building up to a maximum of 5 pounds of weight over 4 weeks.
Intermediate Exercise Program
Terminal Knee Extension, Supine, 10 Repetitions - Lie on your back with a towel roll under your knee. Straighten your knee (still supported by the roll) and hold 5 seconds. Slowly return to the starting position. Repeat 10 times. Advanced: Before starting, add weights to your ankle, starting with 1 pound of weight and building up to a maximum of 5 pounds of weight over 4 weeks.
Straight Leg Raises, 5 Sets, 10 Repetitions - Lie on your back, with your uninvolved knee bent. Straighten your other knee with a quadriceps muscle contraction. Now, slowly raise your leg until your foot is about 12 inches from the floor. Slowly lower it to the floor and relax. Perform 5 sets of 10 repetitions. Advanced: Before starting, add weights to your ankle, starting with 1 pound of weight and building up to a maximum of 5 pounds of weight over 4 weeks.
Partial Squat, with Chair, 10 Repetitions - Hold onto a sturdy chair or counter with your feet 6-12 inches from the chair or counter. Do not bend all the way down. DO NOT go any lower than 90 degrees. Keep back straight. Hold for 5-10 seconds. Slowly come back up. Relax. Repeat 10 times.
Quadricep Stretch - Standing, 10 Repetitions - Standing with the involved knee bent, gently pull heel toward buttocks, feeling a stretch in the front of the leg. Hold for 5 seconds. Repeat 10 times.
Advanced Exercise Program
Knee Bend, Partial, Single Leg - Stand supporting yourself with the back of a chair. Bend your uninvolved leg with your toe touching for balance as necessary. Slowly lower yourself, keeping your foot flat. Don't overdo this exercise. Straighten up to the starting position. Relax and repeat 10 times.
Step-ups, Forward, 10 Repetitions - Step forward up onto a 6-inch high stool, leading with your involved leg. Step down, returning to the starting position. Increase the height of the platform as strength increases. Repeat 10 times.
Step-ups, Lateral, 10 Repetitions - Step up onto a 6-inch high stool, leading with your involved leg. Step down, returning to the starting position. Increase the height of the platform as strength increases. Repeat 10 times.
Terminal Knee Extension, Sitting, 10 Repetitions - While sitting in a chair, support your involved heel on a stool. Now straighten your knee, hold 5 seconds and slowly return to the starting position. Repeat 10 times.
Hamstring Stretch, Supine, 10 Repetitions - Lie on your back. Bend your hip, grasping your thigh just above the knee. Slowly straighten your knee until you feel the tightness behind your knee. Hold for 5 seconds. Relax and repeat 10 times. Repeat with the other leg. If you do not feel this stretch, bend your hip a little more, and repeat. No bouncing! Maintain a steady, prolonged stretch for the maximum benefit.
Hamstring Stretch, Supine at Wall, 10 Repetitions - Lie next to a doorway, with one leg extended. Place your heel against the wall, and, with your knee bent, move your hips toward the wall. Now begin to straighten your knee. When you feel the tightness behind your knee, hold for 5 seconds. Relax and repeat 10 times. The closer you are to the wall, the more intense the stretch. Repeat with the other leg.
Exercise Bike - If you have access to an exercise bike, set the seat high so your foot can barely reach the pedal and complete a full revolution. Set the resistance to "light" and progress to "heavy." Start pedaling for 10 minutes a day. Increase the duration by one minute a day until you are pedaling 20 minutes a day. Walking - An excellent physical exercise activity in the middle stages of your recovery from surgery (after 2 weeks).
Running should be avoided until 6-8 weeks because of the impact and shock forces transmitted to your knee. Both walking and running activities should be gradually phased into your exercise program.
More joint replacement surgeries (arthroplasties) are performed on the knee than on any other joint. In a total knee arthroplasty (TKA), the diseased cartilage surfaces of the thighbone (femur), the shinbone (tibia) and the kneecap (patella) are replaced by prostheses made of metal alloys, high-grade plastics and polymeric materials. Most of the other structures of the knee, such as the connecting ligaments, remain intact.
Knee replacement surgery is generally recommended for patients with severe knee pain and disability caused by damage to cartilage from rheumatoid arthritis, osteoarthritis or trauma. It is highly successful in relieving pain and restoring joint function.
For simplicity, the knee is considered a hinge joint because of its ability to bend and straighten like a hinged door. In reality, the knee is much more complex because the surfaces actually roll and glide as the knee bends. The first implant designs used the hinge concept and literally included a connecting hinge between the components. Newer implant designs, recognizing the complexity of the joint, attempt to replicate the more complicated motions and to take advantage of the posterior cruciate ligament (PCL) and collateral ligaments for support.
Up to three bone surfaces may be replaced during a TKA: the lower ends (condyles) of the thighbone, the top surface of the shinbone and the back surface of the kneecap. Components are designed so that metal always articulates against plastic, which provides smooth movement and results in minimal wear.
1. Femoral component: The metal femoral component curves around the end of the thighbone and has an interior groove so the kneecap can move up and down smoothly against the bone as the knee bends and straightens. Usually, one large piece is used to resurface the end of the bone. If only one side of the thighbone is damaged, a smaller piece may be used (unicompartmental knee replacement) to resurface just that part of the bone. Some designs (posterior stabilized designs) have an internal post with a circular-shaped device (cam) that works with a corresponding tibial component to help prevent the thighbone from sliding forward too far on the shinbone when you bend the knee.
2. Tibial component: The tibial component is a flat metal platform with a polyethylene cushion. The cushion may be part of the platform (fixed) or separate (mobile) with either a flat surface (PCL-retaining) or a raised, sloping surface (PCL-substituting).
3. Patellar component: The patellar component is a dome-shaped piece of polyethylene that duplicates the shape of the kneecap anchored to a flat metal plate.
There are more than 150 knee replacement designs on the market today. Several manufacturers make knee implants. The brand and design used by your doctor or hospital depends on many factors, including your needs (based on your age, weight, activity level and health), the doctor's experience and familiarity with the device, and the cost and performance record of the implant. You may wish to discuss these issues with your doctor.
The metal parts of the implant are made of titanium- or cobalt/chromium-based alloys. The plastic parts are made of ultrahigh-density polyethylene. All together, the components weigh between 15 and 20 ounces, depending on the size selected. The construction materials used must meet several criteria:
- They must be biocompatible; that is, they can function in the body without creating either a local or a systemic rejection response.
- Their mechanical properties must be able to duplicate the structures they are intended to replace; for example, they are strong enough to take weightbearing loads, flexible enough to bear stress without breaking and able to move smoothly against each other as required.
- They must be able to retain their strength and shape for a long time. The chance of a knee replacement lasting 15 to 20 years is about 95 percent.
To date, man-made joints have not solved the problem of wear. Every time bone rubs against bone, or metal rubs against plastic, the friction creates microscopic particulate debris. Just as wear in the natural joint contributed to the need for a replacement joint, wear in the prostheses may eventually require a second (revision) surgery.
During a TKA, the knee is in a bent position so that all the surfaces to be replaced can be exposed. The usual approach is lengthwise through the front of the knee, just to the inside of the kneecap, although some surgeons will approach the joint from the outer side, just above the kneecap. The incision is 6" to 12" long. The large quadriceps muscle and the kneecap are moved to the side to reveal the bone surfaces.
After taking several measurements to ensure that the new implant will fit properly, the surgeon begins to smooth the rough edges of the bones. Depending on the type of implant used, the surgeon may begin with either the thighbone or the shinbone.
Special jigs are used to accurately trim the damaged surfaces at the end of the thighbone. The devices shape the end of the thighbone so it configures to the inside of the prosthesis. The shinbone is cut flat across the bone and a portion of the bone's center is drilled out. The surgeon removes just enough of the bone so that when the prosthesis is inserted, it recreates the joint line at the same level as prior to surgery. If any ligaments around the knee have contracted due to pain and deformity before the surgery, the surgeon carefully releases them so that they function as close to the normal state as possible.
The prostheses are inserted, tested and balanced. The surgeon wants to be sure that the joint line is in the right place and the kneecap is accurately aligned for proper joint movement. If it is necessary to resurface the kneecap, the surgeon will apply a shaped piece of polyethylene that maintains the original width of the kneecap.
The knee replacement may be "cemented," "cementless" or "hybrid," depending on the type of fixation used to hold the implant in place. Although there are certain general guidelines, each case is individual and your surgeon will evaluate your situation carefully before making any decisions. Do not hesitate to ask what type of fixation will be used in your situation and why that choice is appropriate for you.
Knee Ligament Injuries
In 2003 more than 9.5 million people visited orthopaedic surgeons because of knee problems. (Source: National Center for Health Statistics; Centers for Disease Control and Prevention; 2003 National Ambulatory Medical Care Survey.) The knee is the largest joint in the body and is vital to movement. Two sets of ligaments in the knee give it stability: the cruciate and the collateral ligaments.
The cruciate ligaments are located inside the knee joint and connect the thighbone (femur) to the shinbone (tibia). They are made of many strands and function like short ropes that hold the knee joint tightly in place when the leg is bent or straight. This stability is needed for proper knee joint movement.
The name, cruciate, derives from the word crux, meaning cross, and crucial. The cruciate ligaments not only lie inside the knee joint, they crisscross each other to form an "x". The cruciate ligament located toward the front of the knee is the anterior cruciate ligament (ACL), and the one located toward the rear of the knee is called the posterior cruciate ligament (PCL).
The ACL prevents the shinbone from sliding forwards beneath the thighbone. The ACL can be injured in several ways:
- Changing direction rapidly
- Slowing down when running
- Landing from a jump
- Direct contact, such as in a football tackle
Recognizing an ACL injury
If you injure your ACL, you may not feel any pain immediately. However, you might hear a popping noise and feel your knee give out from under you. Within 2 to 12 hours, the knee will swell, and you will feel pain when you try to stand. Apply ice to control swelling and elevate your knee until you can see an orthopaedic surgeon.
If you walk or run on an injured ACL, you can damage the cushioning cartilage in the knee. For example, you may plant the foot and turn the body to pivot, only to have the shinbone stay in place as the thighbone above it moves with the body.
Diagnosing an ACL injury
A diagnosis of ACL injury is based on a thorough physical examination of the knee. The exam may include several tests to see if the knee stays in the proper position when pressure is applied from different directions. Your orthopaedist may order an X-ray and MRI (magnetic resonance imaging) or, in some cases, arthroscopic inspection.
A partial tear of the ACL may or may not require surgical treatment. A complete tear is more serious. Complete tears, especially in younger athletes, may require reconstruction.
Treating ACL tears
Both nonoperative and operative treatment choices are available.
- May be used because of a patient's age or overall low activity level.
- May be recommended if the overall stability of the knee seems good.
- Involves a treatment program of muscle strengthening, often with the use of a brace to provide stability.
- Operative treatment (either arthroscopic or open surgery): Uses a strip of tendon, usually taken from the patient's knee (patellar tendon) or hamstring muscle, that is passed through the inside of the joint and secured to the thighbone and shinbone.
- Is followed by an exercise and rehabilitation program to strengthen the muscles and restore full joint mobility.
The posterior cruciate ligament, or PCL, is not injured as frequently as the ACL. PCL sprains usually occur because the ligament was pulled or stretched too far, a blow to the front of the knee, or a simple misstep.
PCL injuries disrupt knee joint stability because the shinbone can sag backwards. The ends of the thighbone and shinbone rub directly against each other, causing wear and tear to the thin, smooth articular cartilage. This abrasion may lead to arthritis in the knee.
Treating PCL injuries
Patients with PCL tears often do not have symptoms of instability in their knees, so surgery is not always needed. Many athletes return to activity without significant impairment after completing a prescribed rehabilitation program.
However, if the PCL injury pulls a piece of bone out of the top of the shinbone, surgery is needed to reattach the ligament. Knee function after this surgery is often quite good.
The collateral ligaments are located at the inner side and outer side of the knee joint. The medial collateral ligament (MCL) connects the thighbone to the shinbone and provides stability to the inner side of the knee. The lateral collateral ligament (LCL) connects the thighbone to the other bone in the lower portion of your leg (fibula) and stabilizes the outer side.
Injuries to the MCL are usually caused by contact on the outside of the knee and are accompanied by sharp pain on the inside of the knee. The LCL is rarely injured.
Collateral ligament injuries
If the medial collateral ligament (MCL) has a small partial tear, conservative treatment usually works. Remember the acronym RICE: Rest, Ice, Compression, Elevation.
Rest the knee to give the ligament time to heal. Ice can be applied two or three times a day for 15 to 20 minutes each time.
Compress the injury to limit swelling. You may have to wear a bandage or brace for a while.
Elevate the knee whenever possible.
You should also consult your physician about a course of rehabilitation exercises for good healing.
If the collateral ligament is completely torn or torn in such a way that ligament fibers cannot heal, you may need surgery. Repair may bring good results, with a return to good knee stability. After satisfactory rehabilitation, many people resume their previous levels of activity.
A rehabilitation plan is needed if you have a cruciate or collateral ligament injury. Most rehabilitation plans include:
Passive range-of-motion exercises designed to restore flexibility.
Braces to control joint movement.
Exercises to strengthen the quadriceps muscles in the front of the thigh. (Muscle strength is needed to provide the knee joint with as much support and stability as possible when weight is placed on it.)
Additional exercises on a high-seat exercise bicycle, followed by more strenuous quadriceps exercise.
Your progress and the ability of the knee to function as a normal knee will determine how long you must use crutches and a brace.
Knee Replacement Exercise Guide
Regular exercise to restore your knee mobility and strength and a gradual return to everyday activities are important for your full recovery. Your orthopaedic surgeon and physical therapist may recommend that you exercise approximately 20 to 30 minutes two or three times a day and walk 30 minutes, two or three times a day during your early recovery. Your orthopaedist may suggest some of the following exercises.The following guide can help you better understand your exercise/activity program, supervised by your therapist and orthopaedic surgeon.
Early Post-operative Exercises
Start the following exercises as soon as you are able. You can begin these in the recovery room shortly after surgery. You may feel uncomfortable at first, but these exercises will speed your recovery and actually diminish your post-operative pain.
Quad Sets - Tighten your thigh muscle. Try to straighten your knee. Hold for 5 to 10 seconds. Repeat this exercise approximately 10 times during a two minute period, rest one minute and repeat. Continue until your thigh feels fatigued.
Straight Leg Raises - Tighten the thigh muscle with your knee fully straightened on the bed, as with the Quad set. Lift your leg several inches. Hold for five to 10 seconds. Slowly lower. Repeat until your thigh feels fatigued. You also can do leg raises while sitting. Fully tighten your thigh muscle and hold your knee fully straightened with your leg unsupported. Repeat as above. Continue these exercises periodically until full strength returns to your thigh.
Ankle Pumps - Move your foot up and down rhythmically by contracting the calf and shin muscles. Perform this exercise periodically for two to three minutes, two or three times an hour in the recovery room. Continue this exercise until you are fully recovered and all ankle and lower-leg swelling has subsided.
Knee Straightening Exercises - Place a small rolled towel just above your heel so that it is not touching the bed. Tighten your thigh. Try to fully straighten your knee and to touch the back of your knee to the bed. Hold fully straightened for five to 10 seconds. Repeat until your thigh feels fatigued.
Bed-Supported Knee Bends - Bend your knee as much as possible while sliding your foot on the bed. Hold your knee in a maximally bent position for 5 to 10 seconds and then straighten. Repeat several times until your leg feels fatigued or until you can completely bend your knee.
Sitting Supported Knee Bends - While sitting at bedside or in a chair with your thigh supported, place your foot behind the heel of your operated knee for support. Slowly bend your knee as far as you can. Hold your knee in this position for 5 to 10 seconds. Repeat several times until your leg feels fatigued or until you can completely bend your knee.
Sitting Unsupported Knee Bends - While sitting at bedside or in a chair with your thigh supported, bend your knee as far as you can until your foot rests on the floor. With your foot lightly resting on the floor, slide your upper body forward in the chair to increase your knee bend. Hold for 5 to 10 seconds. Straighten your knee fully. Repeat several times until your leg feels fatigued or until you can completely bend your knee.
Soon after your surgery, you will begin to walk short distances in your hospital room and perform everyday activities. This early activity aids your recovery and helps your knee regain its strength and movement.
Walking - Proper walking is the best way to help your knee recover. At first, you will walk with a walker or crutches. Your surgeon or therapist will tell you how much weight to put on your leg. Stand comfortably and erect with your weight evenly balanced on your walker or crutches. Advance your walker or crutches a short distance; then reach forward with your operated leg with your knee straightened so the heel of your foot touches the floor first. As you move forward, your knee and ankle will bend and your entire foot will rest evenly on the floor. As you complete the step, your toe will lift off the floor and your knee and hip will bend so that you can reach forward for your next step. Remember, touch your heel first, then flatten your foot, then lift your toes off the floor.
Walk as rhythmically and smooth as you can. Don't hurry. Adjust the length of your step and speed as necessary to walk with an even pattern. As your muscle strength and endurance improve, you may spend more time walking. You will gradually put more weight on your leg. You may use a cane in the hand opposite your surgery and eventually walk without an aid. When you can walk and stand for more than 10 minutes and your knee is strong enough so that you are not carrying any weight on your walker or crutches (often about two to three weeks after your surgery), you can begin using a single crutch or cane. Hold the aid in the hand opposite the side of your surgery. You should not limp or lean away from your operated knee.
Stair Climbing and Descending - The ability to go up and down stairs requires strength and flexibility. At first, you will need a handrail for support and will be able to go only one step at a time. Always lead up the stairs with your good knee and down the stairs with your operated knee. Remember, "up with the good" and "down with the bad." You may want to have someone help you until you have regained most of your strength and mobility.
Stair climbing is an excellent strengthening and endurance activity. Do not try to climb steps higher than the standard height (7 inches) and always use a handrail for balance. As you become stronger and more mobile, you can begin to climb stairs foot over foot.
Advanced Exercises and Activities
Once you have regained independence for short distances and a few steps, you may increase your activity. The pain of your knee problems before surgery and the pain and swelling after surgery have weakened your knee. A full recovery will take many months. The following exercises and activities will help you recover fully.
Standing Knee Bends - Standing erect with the aid of a walker or crutches, lift your thigh and bend your knee as much as you can. Hold for 5 to 10 seconds. Then straighten your knee, touching the floor with your heel first. Repeat several times until fatigued.
Assisted Knee Bends - Lying on your back, place a folded towel over your operated knee and drop the towel to your foot. Bend your knee and apply gentle pressure through the towel to increase the bend. Hold for 5 to 10 seconds; repeat several times until fatigued.
Knee Exercises with Resistance - You can place light weights around your ankle and repeat any of the above exercises. These resistance exercises usually can begin four to six weeks after your surgery. Use one- to two-pound weights at first; gradually increase the weight as your strength returns. (Inexpensive wrap-around ankle weights with Velcro straps can be purchased at most sporting goods stores.)
Exercycling - Exercycling is an excellent activity to help you regain muscle strength and knee mobility. At first, adjust the seat height so that the bottom of your foot just touches the pedal with your knee almost straight. Peddle backward at first. Ride forward only after a comfortable cycling motion is possible backwards. As you become stronger (at about four to six weeks) slowly increase the tension on the exercycle. Exercycle for 10 to 15 minutes twice a day, gradually build up to 20 to 30 minutes, three or four times a week.
Pain or Swelling after Exercise - You may experience knee pain or swelling after exercise or activity. You can relieve this by elevating your leg and applying ice wrapped in a towel. Exercise and activity should consistently improve your strength and mobility. If you have any questions or problems, contact your orthopaedic surgeon or physical therapist.
Kneecap (Prepatellar) Bursitis
Plumbers, carpet layers and other people who spend a lot of time on their knees often experience swelling in the front of the knee. The constant friction irritates a small lubricating sac (bursa) located just in front of the kneecap (patella). The bursa enables the kneecap to move smoothly under the skin. If the bursa becomes inflamed, it fills with fluid and causes swelling at the top of the knee. This condition is called prepatellar bursitis.
Who's at risk
- People who constantly kneel to work, such as plumbers, roofers, carpet layers, coal miners or gardeners.
- Athletes who participate in sports where direct blows or falls on the knee are common, such as football, wrestling or basketball.
- Someone who has been in a motor vehicle collision.
- People with rheumatoid arthritis or gout.
- Pain with activity, but not usually at night.
- Rapid swelling on the front of kneecap.
- Tender and warm to the touch.
Your doctor may first recommend an X-ray to rule out the possibility of a fracture. Conservative treatment is usually effective, as long as the bursa is simply inflamed and not infected.
- Rest. Discontinue the activity or substitute another activity until the bursitis clears up.
- Apply ice at regular intervals three or four times a day for 20 minutes at a time. Each session should reduce swelling considerably if the knee is also being rested.
- Elevate the affected leg except when necessary to walk.
- Take an anti-inflammatory medication such as aspirin or ibuprofen.
If the swelling is significant, your physician may decide to drain (aspirate) the bursa with a needle. Chronic swelling that causes disability may also be treated by draining the bursa, but if the swelling continues, your orthopaedic surgeon may recommend surgical removal of the bursa. The operation is an outpatient procedure. It takes a few days for the knee to regain its flexibility and some weeks before normal activities can be resumed.
Preventing knee bursitis
You can help prevent bursitis by following these simple recommendations:
1. Wear kneepads if you work on your knees or participate in high-risk sports such as football, basketball or wrestling.
2. Rest your knees regularly by stopping to stretch your legs. You may also wish to consider switching activities on a regular basis to avoid prolonged stress on your knees.
3. Apply ice and elevate your knees after a workout.
One of the most commonly injured parts of the knee, the meniscus is a wedge-like rubbery cushion where the major bones of your leg connect. Meniscal cartilage curves like the letter "C" at the inside and outside of each knee. A strong stabilizing tissue, the meniscus helps the knee joint carry weight, glide and turn in many directions. It also keeps your femur (thighbone) and tibia (shinbone) from grinding against each other.
Football players and others in contact sports may tear the meniscus by twisting the knee, pivoting, cutting or decelerating. In athletes, meniscal tears often happen in combination with other injuries such as a torn ACL (anterior cruciate ligament). Older people can injure the meniscus without any trauma as the cartilage weakens and wears thin over time, setting the stage for a degenerative tear.
Signs and symptoms
You might experience a "popping" sensation when you tear the meniscus. Most people can still walk on the injured knee and many athletes keep playing. When symptoms of inflammation set in, your knee feels painful and tight. For several days you have:
- Stiffness and swelling.
- Tenderness in the joint line.
- Collection of fluid ("water on the knee").
Without treatment, a fragment of the meniscus may loosen and drift into the joint, causing it to slip, pop or lock—your knee gets stuck, often at a 45-degree angle, until you manually move or otherwise manipulate it. If you think you have a meniscal tear, see your doctor right away for diagnosis and individualized treatment.
Tell your doctor exactly what happened and when. He or she may conduct physical testing to evaluate the extent of your meniscal tear. You may need X-rays to rule out osteoarthritis or other possible causes of your knee pain. Sometimes your doctor may use a magnetic resonance imaging scan to get a better look at the soft tissues of your knee joint. Your doctor may also use a miniature telescope (arthroscope) to see into your knee joint, especially if your knee locks.
Menisci tear in a number of different ways:
- Young athletes often get longitudinal or "bucket handle" tears if the femur and tibia trap the meniscus when the knee turns.
- Less commonly, young athletes get a combination of tears called radial or "parrot beak" in which the meniscus splits in two directions due to repetitive stress activities such as running.
- In older people, cartilage degeneration that starts at the inner edge causes a horizontal tear as it works its way back.
Initial treatment of a meniscal tear follows the basic RICE formula: rest, ice, compression and elevation, combined with nonsteroidal anti-inflammatory medications for pain. If your knee is stable and does not lock, this conservative treatment may be all you need. Blood vessels feed the outer edges of the meniscus, giving that part the potential to heal on its own. Small tears on the outer edges often heal themselves with rest.
If your meniscal tear does not heal on its own and your knee becomes painful, stiff or locked, you may need surgical repair. Depending upon the type of tear, whether you also have an injured ACL, your age and other factors, your doctor may use an arthroscope to trim off damaged pieces of cartilage.
A cast or brace immobilizes your knee after surgery. You must complete a course of rehabilitation exercises before gradually resuming your activity.
The meniscus (the plural is menisci) is a C-shaped cartilage cushion in the knee joint that helps the joint bear weight, glide and turn. Each knee has two menisci, one on each side, that serve as shock absorbers. An orthopaedic surgeon may be able to repair a damaged or torn meniscus. However, a meniscus that is badly damaged or has an extensive tear may have to be removed. Without the menisci, a knee joint can develop persistent pain, swelling and arthritis.
In older patients, a knee joint replacement is an option. But for younger individuals (those under 50 or 55 years old) there is an alternative to replacing the entire joint. It's called a meniscal transplant and it uses donor tissue to replace the damaged meniscus. This procedure is still relatively uncommon and is not appropriate for all patients. However, patients who qualify can benefit from a meniscal transplant.
Who is eligible for a meniscal transplant?
A meniscal transplant may be recommended for people who meet the following criteria:
- Physically active and relatively young, under age 55
- Missing more than half of the meniscus due to surgery or injury or has a tear that cannot be repaired
- Continues to have activity-related pain in the knee
- Has little or no evidence of arthritis in the knee
Where does the transplanted tissue come from?
As yet, there is no synthetic meniscal tissue. The transplanted tissue comes from human donors. Healthy tissues are frozen and matched by size to the candidate.
How safe is the donor tissue?
The safety of donor tissue is strictly monitored by the Food and Drug Administration and the American Association of Tissue Banks. Before the transplant is performed, the donor tissue is tested to make sure it is disease-free. Tissues are tested to ensure that they do not have any traces of infectious diseases such as hepatitis or HIV/AIDS. These tests help reduce the risk of contamination. You're twice as likely to be struck by lightning (odds: 1 in 800,000) than to develop HIV from a meniscal transplant (odds: 1 in 1.6 million).
How is the surgery performed?
A meniscal transplant is an outpatient procedure performed using tiny instruments and a small incision (arthroscopic surgery). A regional anesthetic is used. The surgeon will make one small incision in the knee joint, with two or three other "nicks" to help situate the transplant properly. These secondary incisions are so small that they may not even require sutures to close them. The new meniscal tissue is anchored to the tibia, the larger bone in your lower leg.
How long is the recovery period?
For the first three to four weeks after surgery, you will have to use crutches and wear a knee brace or immobilizer. This gives the transplanted tissue time to become firmly attached to the bone. If you work in an office and have a basically sedentary job, you should be able to return to work a week after your surgery. If you have a more active job, you may not be able to resume all your job duties for two to three months.
After a month, you can start an exercise therapy program that involves weight-bearing exercises. In many cases, you may be able to return to running after three or four months, and to other recreational activities after five or six months. You should not do certain kinds of activities, such as squatting, bicycling or swimming, for at least six months after surgery.
Are there any complications to the surgery?
With any surgery, there are some risks. However, the risk of complications from meniscal transplants is very slight, less than one percent. The two most common complications are infections and tissue rejection.
How successful are meniscal transplants?
Orthopaedic surgeons have been doing meniscal transplants for several years. In 80 percent to 90 percent of cases, they are effective in relieving activity-related pain and swelling. However, long-term results are not yet available. It's also not known whether the transplant will delay or slow the development of arthritis or other degenerational changes in the knee.
Meniscal transplants aren't right for every patient. If you already have arthritis in your knee, a meniscal transplant may not help you. But in a select group of patients, meniscal transplants offer significant benefits.
Minimally Invasive Total Knee Replacement
Total knee replacement (arthroplasty) is a surgery that is performed for severe degeneration of the knee joint. More than 300,000 people undergo the procedure each year. Minimally invasive total knee arthroplasty is one method of performing a knee replacement. It uses a smaller incision. Knees wear out for a variety of reasons. These include inflammation from arthritis, injury or simple wear and tear. A knee replacement is the resurfacing of the worn out surfaces of the knee. A surgeon replaces lost cartilage with metal and plastic. This is typically done through an incision down the center of the knee. The incision averages 8 inches to 10 inches long. Minimally invasive total knee arthroplasty is a different way of performing the surgery. It uses an incision that is only 4 inches to 6 inches long. This means that potentially there will be less damage to the tissue around the knee.
Arthritis can run in families. Most knee arthritis is due to a lifetime of wear and tear. Nobody knows why some people get severe arthritis, while others don't. Nobody knows why one knee in the same person gets arthritis, while the other does not. Previous injury and obesity are some known causes of arthritis.
Knee arthritis leads to pain. The pain often happens with activity. The knee can also hurt at rest. Patients often find it difficult to go up or down stairs, walk distances or get up from low seats. There may also be swelling, stiffness or a feeling of looseness.
The first steps in treating knee arthritis are activity modification, a program of regular exercise and weight loss. The muscles around the knee protect it during activity. Every step puts several times your body weight through your knee. Improved strength and decreased body weight will prolong the life of your knee. Soft knee braces and modifications of your shoe can sometimes help. Tylenol® or anti-inflammatories (NSAIDs) are usually the first medications recommended for arthritis. Some dietary supplements might also help. You may need to use a cane or walker. This can help you walk and improve your mobility.
The next step is injections. Steroids may be used to decrease inflammation. A lubricant may be used to improve the function of the knee. These can offer some relief. They can be repeated from time to time if they help.
Treatment Options: Surgical
Surgery is the final step in the treatment of knee arthritis. A knee replacement can help to eliminate most of the pain from arthritis. It is indicated if the steps above have failed and the pain from the arthritis is limiting your lifestyle and activities.
Surgical options include knee arthroscopy (although this is rarely used just for arthritis), partial knee replacement and total knee replacement.
Total knee replacement can be performed in the traditional method (8 inch to 10 inch incision). Or it can be performed using newer techniques (4 inch to 6 inch incision). The goal of knee replacement is to provide a pain-free knee that allows relatively normal activities and lasts for as long as possible. In order to achieve these goals, it is extremely important that the knee replacement be inserted in the best possible position. The bone and ligaments are prepared very carefully to allow the knee to be functional and durable. Using the current techniques, 90 percent to 95 percent of knee replacements should last 15 years or longer.
The minimally invasive knee replacement technique attempts to accomplish all of this through a smaller incision. With the smaller incision come the potential benefits of a shorter hospital stay, a shorter recovery and a better looking scar. There is no reason to believe that the knee will function any better. Although there is no question that a knee can be put in through a smaller incision, it is still unknown whether it can be done as well. New ways to open the knee may be more important than the length of the incision. These are sometimes called "quad-sparing" because they protect the quadriceps (the muscle on the front of the thigh) and make the recovery easier.
Several early studies of MIS knee surgery have shown some benefits such as less blood loss, shorter hospital stays and better motion, while others have shown a higher rate of complications, suboptimal positioning of the knee implants and no real difference in the recovery. Unfortunately, we won't know if these new techniques affect the long-term function and durability of the knee replacement for 10 to 15 years. Long-term durability is much more important than whether you were in the hospital for 2 days or 4 days after surgery.
Research on the Horizon/What's New?
Advocates of minimally invasive knee replacement are working to address concerns about accurate positioning of the knee replacement. They are combining the small incision with computer-guided instruments. The potential benefits, risks and costs of this are not yet established.
Nonsurgical Treatment Options for Osteoarthritis of the Knee
If you have osteoarthritis of the knee (OA Knee), you can take advantage of a wide range of treatment options. Only one in four people with OA Knee need surgery, but the effectiveness of different treatments varies from person to person. The choice of treatment should be a joint decision between you and your physician.
The purpose of treatment is to reduce pain, increase function and generally reduce your symptoms. Patient satisfaction is a fundamental goal in treating OA Knee. Treatment options can be nonsurgical or surgical. Nonsurgical treatments fall into four major groups:
- Health and behavior modifications, such as physical therapy and exercise, weight loss and education
- Drug therapy, such as pain relievers or COX-2 inhibitors (drugs that interrupt the cycle of inflammation)
- Intra-articular (within the joint) treatments, such as injections
- Alternative therapies such as herbal remedies, acupuncture or magnet therapy
Here is some information about various nonsurgical treatment options that you might want to discuss with your physician.
Health and behavior modifications
Health and behavior modifications include:
- Patient education
- Physical therapy and exercise
- Weight loss
- Use of a knee brace
The more you understand about your condition, the better prepared you are to make decisions about your care. Patient education focuses on understanding the disease, learning about treatment options, and working with your physician to develop exercise and pain management programs suited to your life. It is based on the belief that your personal actions and behavior changes can reduce the impact of the disease.
Physical therapy and exercise are often effective in reducing pain and improving function. Your physician or a physical therapist can help develop an individualized exercise program that meets your needs and lifestyle.
Many, but not all, people with OA Knee are overweight. Simple weight loss can reduce stress on weightbearing joints, such as the knee. Losing weight can result in reduced pain and increased function, particularly in walking.
Some research studies have focused on the use of knee braces for treatment of OA Knee. They may be especially helpful if the arthritis is centered on one side of the knee. A brace can assist with stability and function. There are two types of braces that are often used. An "unloader" brace shifts load away from the affected portion of the knee. A "support" brace helps support the entire knee load. In most studies, the knee symptoms improved, with a decrease in pain on weightbearing and a general ability to walk longer distances.
Several types of drugs are used to treat OA Knee. Among these are:
- Simple pain relievers
- Nonsteroidal anti-inflammatory drugs (NSAIDs)
- COX-2 inhibitors
- Glucosamine/chondroitin sulfate
Simple pain relievers such as Tylenol are available without a prescription and can be very effective in reducing pain. Pain relievers are usually the first choice of therapy for OA Knee. All drugs have potential side effects and simple analgesics are no exception. In addition, with time, your body can build up a tolerance, reducing the effects of the pain reliever. It is important to realize that these medications, although purchased over-the-counter, can also interact with other medications you are taking, such as blood-thinners. Be sure to discuss these issues with your orthopaedist or primary physician.
A more potent type of pain reliever is a nonsteroidal anti-inflammatory drug or NSAID. These drugs, which include brands such as Motrin, Advil and Aleve, are available in both over-the-counter and prescription forms. Like all pain relievers, NSAIDs can cause side effects including changes in kidney and liver function as well as a reduction in the ability of blood to clot. These effects are usually reversible when the medication is discontinued.
A COX-2 inhibitor is a special type of NSAID that is often prescribed if knee pain is moderate to severe. Common brand names of COX-2 inhibitors include Celebrex and Vioxx. It should be noted that Vioxx was recently withdrawn from the market by its manufacturer. COX-2 inhibitors reduce pain and inflammation so that you can function better. If you are taking a COX-2 inhibitor, you should not use a traditional NSAID (prescription or over-the-counter). Be sure to tell your doctor if you have had a heart attack, stroke, angina, blood clot or hypertension or if you are sensitive to aspirin, sulfa drugs or other NSAIDs.
COX-2 inhibitors can have side effects, including abdominal pain, nausea and indigestion. Antacids or a fatty meal can limit the body's ability to absorb and use COX-2 inhibitors, so do not take them together. These drugs are less irritating to the stomach than other NSAIDs, but abdominal bleeding can occur, sometimes without warning.
Glucosamine and/or chondroitin sulfate may be particularly helpful in the early stages of OA Knee, provided they are used as directed on package inserts and with caution. These are two large molucules that are found in the cartilage of our joints. Supplements sold over-the-counter are usually made from synthetic or animal products. Although glucosamine and chondroitin sulfate are natural substances, sometimes classified as food additives, they can cause side effects such as headaches, stomach upset, nausea, vomiting, and skin reactions. These supplements can interact with other medications, so keep your doctor informed about your use of them.
These substances can help reduce swelling and tenderness, as well as improve mobility and function. If you decide to take this therapy, it is important not to discontinue too soon. At least two months of continuous use is necessary before the full effect is realized.
"Intra-articular" means within the joint itself. These treatments involve one or more injections into the knee joint. There are two types of intra-articular treatments:
Viscosupplementation with hyaluronic acid
Corticosteroid injections are given for moderate to severe pain. They can be very useful if there is significant swelling, but are not very helpful if the arthritis affects the joint mechanics. Corticosteroids or cortison are natural substances known as hormones. They are produced by the adrenal glands in the human body. They can provide pain relief and reduce inflammation with a subsequent increase in quadriceps (thigh muscle) strength. However, the effects are not long-lasting, and no more than four injections should be given per joint per year.
In addition, there is some concern about the use of these injections. For example, pain and swelling may "flare" immediately after the injection, and the potential exists for long-term joint damage or infection. With frequent repeated injections or over an extended period of time, joint damage can actually increase rather than decrease.
Viscosupplementation is a way of adding fluid to lubricate the joint and make it easier to move. This substance is a concentrate of hyaluronic acid, a molecule that is found in the joints of the body. There is less fluid in a knee with osteoarthritis than in a healthy knee. Three to five weekly shots are needed to reduce the pain, but the pain relief is not permanent. Many patients experience improvement for weeks to months, however, and find the process highly worthwhile.
Viscosupplementation can be helpful for people whose arthritis has not responded to behavior modification or basic drug treatments. It is most effective if the arthritis is in its early states (mild to moderate). Sometimes, patients feel pain at the injection site, and occasionally the injections result in an increase in pain and swelling.
Alternative therapies include the use of acupuncture and magnetic pulse therapy. Many forms of therapy are unproven, but reasonable to try, provided you find a qualified practitioner and keep your physician informed of your decisions.
Acupuncture is adapted from a Chinese medical practice. It uses fine needles to stimulate specific body areas to relieve pain or temporarily numb an area. Although it is used in many parts of the world and evidence suggests that it can help ease the pain of arthritis, there are few scientific studies of its effectiveness. Studies that have been done seem to indicate that acupuncture is better at relieving pain than at improving function. The most common risk is the potential for infection and disease transmission from the use of nonsterile needles. Be sure your acupuncturist is certified, and do not hesitate to ask about his or her sterilization practices.
Magnetic pulse therapy is another alternative that may be helpful in reducing the pain of OA Knee. It's painless and works by applying a pulsed signal to the knee, which is placed in an electromagnetic field. Because the body produces electrical signals, scientists think that magnetic pulse therapy may stimulate the production of new cartilage. However, like many alternative therapies, magnetic pulse therapy has yet to be proven. Before attempting any therapy on your own, talk to your physician. Together, you can develop a program that will increase your understanding of arthritis, help ease your pain and improve the functioning of your joints.
Osgood-Schlatter Disease (Knee Pain)
A common form of growing pains or overuse in early adolescence involves the shinbone and the knee. The shinbone (tibia) has a raised area just below the kneecap called the tibial tubercle. The tubercle has two important functions:
- It contributes to the growth of the leg.
- It is where the thigh muscle attaches to the shinbone through the kneecap tendon.
Swelling, enlargement of the tubercle and pain are common in kids with year round sports schedules.
Risk Factors / Prevention
Those who participate in certain sports are at risk. These sports include soccer, gymnastics, basketball and distance running.
Once the diagnosis is made, treatment is aimed at diminishing the severity or intensity of the pain and swelling. Treatment of symptoms includes taking scheduled doses of Advil or Aleve, and wrapping the knee. This is recommended until the child can enjoy sports activities without discomfort or significant pain afterwards. Weakness and pain that gets worse with activity may require rest for several months, followed by a conditioning program. In some susceptible teenagers, Osgood-Schlatter symptoms may last for 2 to 3 years. However, most symptoms will completely resolve with completion of the growth spurt. This happens at around age 14 for girls and 16 for boys.
Osteonecrosis of the Knee
Knee pain has many causes. A relatively common cause of knee pain in older women occurs when a segment of bone loses its blood supply and begins to die. This condition is called osteonecrosis, which literally means "bone death."
In the knee, the knobby portion of the thighbone on the inside of the knee (the medial femoral condyle) is most often affected. However, osteonecrosis of the knee may also occur on the outside of the knee (the lateral femoral condyle) or on the flat top of the lower leg bone (tibial plateau).
The exact cause of the disease is not yet known. One theory is that a stress fracture, combined with a specific activity or trauma, results in an altered blood supply to the bone. Another theory supposes that a build-up of fluid within the bone puts pressure on blood vessels and diminishes circulation. More than 3 times as many women as men are affected; most are over 60 years of age.
Osteonecrosis of the knee is also associated with certain conditions and treatments, such as obesity, sickle cell anemia, lupus, kidney transplants, and steroid therapy. Steroid-induced osteonecrosis frequently affects multiple joints and is usually seen in young patients. Regardless of the cause, if the disease is not identified and treated early, it can develop into severe osteoarthritis.
Signs and symptoms
- Sudden pain on the inside of the knee, perhaps triggered by a specific activity or minor injury
- Increased pain at night and with activity
- Swelling over the front and inside of the knee
- Heightened sensitivity to touch in the area
- Limited motion due to pain
Osteonecrosis of the knee develops through four stages, which can be identified by symptoms and X-rays.
Stage I: Symptoms are most intense in the earliest stage. Symptoms may continue for 6 to 8 weeks and then subside. Because X-rays are normal, a positive bone scan is needed to make the diagnosis. Treatment at this point is nonoperative and conservative, focusing on pain relief and protected weight-bearing.
Stage II: It may take several months for the disease to progress to Stage II. At this point, X-rays will show that the rounded edge of the thighbone is starting to flatten out. An MRI or bone scan can be used to diagnose the disease. A CT scan may also be used to measure the affected area of bone area.
Stage III: By the time the disease reaches stage III (3 to 6 months after onset), it is clearly visible on X-rays and no other diagnostic tests are needed. The articular cartilage covering the bone begins to loosen as the bone itself begins to die. Operative treatments may be considered at this point.
Stage IV: At this point, the bone begins to collapse. The articular cartilage is destroyed, the joint space narrows, and bone spurs may form. Severe osteoarthritis results and joint replacement surgery may be necessary.
In the early stages of the disease, treatment is nonoperative. If the affected area is small, this treatment may be all that is needed. Options include:
- Medications to reduce the pain
- A brace to relieve pressure on the joint surface
- A conditioning program with exercises to increase the strengthen of the muscles in your thighs
- Activity modifications to reduce knee pain
If more than half of the bone surface is affected, you may need surgical treatment. Several different procedures may be used to treat osteonecrosis of the knee. Among the surgical options are:
- Arthroscopic cleansing (debridement) of the joint
- Drilling to reduce pressure on the bone surface
- Procedures to shift weight-bearing away from the affected area
- Replacement of one or both joint surfaces
Your orthopaedic surgeon will discuss the options with you and make a recommendation based on your individual situation.
Osteotomy and Unicompartmental Knee Arthroplasty
Total joint replacement (arthroplasty) is a common and very successful surgery for people with degenerative arthritis (osteoarthritis) of the knee. Two other surgeries can also restore knee function and significantly diminish osteoarthritis pain in carefully selected patients. If osteoarthritis damage to your knee meets certain qualifications, a doctor may recommend either osteotomy or unicompartmental knee arthroplasty (UKA).
Osteoarthritis damage to the knee
A normal knee glides smoothly because articular cartilage covers the ends of the bones that form joints. Osteoarthritis damages the cartilage, progressively wearing it away. The ends of the bones become rough like pieces of sandpaper. Damaged cartilage can cause the joint to "stick" or lock when you use it. Your knee may get painful, stiff and lose range of motion. See your doctor to diagnose osteoarthritis.
Provide your complete medical history including detailed descriptions of osteoarthritis symptoms and when they began. Have you tried nonsurgical treatments such as rest, weight loss and nonsteroidal anti-inflammatory medication for pain? Does it hurt too much to get dressed, bathe or walk up stairs? The doctor will check your knee's range of motion, ligament stability and angular deformity. He or she will observe your knees while you stand and walk, and examine your hips, feet and ankles. Both knees will probably be X-rayed.
Your doctor's recommendation of a surgical procedure for osteoarthritis knee repair depends in part upon how it is damaged. The knee has three joints (compartments), any or all of which can be impacted by osteoarthritis:
- The inside (medial) compartment (medial tibial plateau and medial femoral condyle) is most commonly involved, producing a bowleg (genu varum) deformity.
- The outside (lateral) compartment (lateral tibial plateau and lateral femoral condyle) is sometimes involved in women or obese people, producing a knock-knee (genu valgum) deformity.
- The kneecap (patellofemoral) compartment (patella and femoral trochlear notch) may also develop osteoarthritis.
If you have early stage arthritis confined to one part of the knee, your doctor may recommend osteotomy or UKA.
Osteotomy may be appropriate if you are younger than age 60, active or overweight. There must also be uneven damage to the joint, correctable deformity and no inflammation. The surgeon reshapes the shinbone (tibia) or thighbone (femur) to improve your knee's alignment. The healthy bone and cartilage is realigned to compensate for the damaged tissue. Knee osteotomy surgically repositions the joint, realigning the mechanical axis of the limb away from the diseased area. This lets your knee glide freely and carry weight evenly on a more normal compartment.
Proximal tibial valgus osteotomy treats arthritis of the medial compartment, correcting a knee that angles inward (varus deformity).
Distal femoral varus osteotomy treats arthritis of the lateral compartment, correcting a knee that angles outward (valgus deformity).
The doctor may use one of several techniques to hold the joint in place (i.e., immobilization with a cast, staples or internal plate devices).
Outcome: Osteotomy relieves pain and may delay the progression of osteoarthritis. Cosmetically, the knee may not look symmetrical after osteotomy. There's a chance you will eventually need TKA, which can be a more technically challenging procedure after you've had an osteotomy. Infections and other complications are possible. Depending upon how quickly you heal, you will need to walk with crutches for 1-3 months. After that you begin rehabilitative leg strengthening and walking exercises. You may be able to resume your full activities after 3-6 months.
Unicompartmental knee arthroplasty
Unicompartmental knee arthroplasty (UKA) may be appropriate if you are age 60 or older, not obese and relatively sedentary. Among other specific qualifications, your knee must have:
- An intact anterior cruciate ligament (ACL).
- No significant inflammation.
- No damage to the other compartments, calcification of cartilage or dislocation.
Your doctor will verify that your knee meets the requirements when he or she begins the surgery. (Note: If your knee does not meet the qualifications, you may need TKA.) The surgeon removes diseased bone and puts an implant (prosthesis) in its place. The two small replacement parts are secured to the rest of your knee. You can get UKA surgery on both knees at the same time if you need it.
Outcome: UKA aleviates pain and may delay the need for TKA. You get better joint motion and function because the procedure preserves both cruciate ligaments and other healthy parts of the knee. You also keep the bone stock in the kneecap joint and the other compartment, which can be helpful if you ever need conversion to TKA in the future. Complications are rare, but the new joint could develop an infection or slip out of place after surgery. For these reasons, your doctor may want to see you for follow-up visits after surgery. You will have to do range of motion and other physical therapy exercises to rehabilitate your knee. Recovery from UKA is faster than from TKA or osteotomy.
Although UKA was a controversial procedure when it was first introduced about 30 years ago, success rates have improved thanks to precise patient selection, refined surgical techniques and improved implant design. UKA has a higher initial success rate and fewer complications compared with osteotomy. Other advantages include less blood loss during surgery and cheaper cost.
Posterior Cruciate Ligament (PCL) Tear
Most sports fans have heard about ACL (anterior cruciate ligament) injuries and the damage they do. But little attention is paid to a corresponding ligament in the knee, the PCL, or posterior cruciate ligament. The connective tissues called ligaments provide stability and help control movement. The PCL is located in the back of the knee and connects the thighbone (femur) to the shinbone (tibia) to prevent the shinbone from moving too far backward.
The PCL is very strong, but a powerful force can rupture or tear it. For example, PCL tears can occur when a football or soccer player falls on a bent knee. Motor vehicle accidents are another common cause of injury to the PCL. When the driver or passenger strikes the bent knee just below the kneecap (patella) against the dashboard, the force can tear the PCL and damage other ligaments, bones and muscles. Excessive tension, such as results from a dislocated knee, can also damage the PCL.
Signs and symptoms
- Marked, immediate swelling (within three hours of the injury)
- Difficulty walking after the injury
- Painful to move the knee
- Occasionally, a feeling of instability, or the knee "giving way"
To determine the extent of the injury, the physician relies on an account of the accident, a visual examination, and several diagnostic tests. The doctor will need to know if you have a history of knee injuries. During the examination, the doctor will compare the injured leg with the normal leg and see if there is any sag or movement in the shinbone. PCL injuries may be isolated or combined.
Isolated PCL injuries:
- Can usually be treated nonsurgically
- Do not involve any other structures in the knee
- May be either partial or complete tears
Combined PCL injuries
- May involve injury to other ligaments, bone, nerves or blood vessels
- Usually require surgical repair
An MRI (magnetic resonance image) can be used to confirm the diagnosis. X-rays do not show ligaments, but they can reveal any associated damage to the bones and cartilage. For example, if the PCL is torn completely from its attachment to the shinbone, it may take a piece of bone as well. This is called an avulsion fracture and can be seen on an X-ray.
The type of injury dictates the type of treatment you need. For minor PCL tears, the initial treatment is RICE: rest, ice, compression and elevation. You may have to use crutches for a short time, and your doctor may prescribe some anti-inflammatory drugs such as aspirin or ibuprofen. After the swelling subsides, you will need to follow a program of physical therapy to strengthen your quadriceps muscle and regain range of motion.
Some patients require surgery to stabilize the knee. Arthroscopic surgery, which uses small incisions and pencil-sized instruments, is used to determine and repair damage to the cartilage in the knee. Avulsion fractures may need to be fixed with internal screws to ensure proper healing. If the PCL is completely torn, it may be reconstructed using a portion of the patellar tendon or some other autograph.
The goals of rehabilitation are to restore range of motion and to strengthen the quadriceps muscles, which help stabilize the knee. After surgery, you may have to use crutches and a knee brace. Exercises such as squats and leg presses are used because they put less stress on the knee. Full recovery takes several months.
Rotating Platform/Mobile-bearing Knees
The largest, strongest and heaviest joints in the body, knees provide support and mobility and carry almost half the body's weight. Functioning like a hinge where the lower end of the femur (thighbone) rotates on the upper end of the tibia (shinbone) and patella (kneecap), a healthy knee lets you move your lower leg forward and backward, and swivel slightly to point the toes in or out. Ligaments and cartilage stabilize and support the joint, preventing it from moving too far from side to side.
If osteoarthritis wears away a knee joint's articular cartilage, your doctor may recommend total knee arthroplasty (replacement), a common and successful procedure that improves knee motion and lets you resume relatively normal activities without pain. An orthopaedic surgeon resurfaces the knee joint, replacing damaged and worn weight-bearing surfaces with a prosthesis (implant) made of metal alloys, ceramic material or high-density plastic parts which may be joined to bone by acrylic cement.
Fixed- vs. mobile-bearing
Most people get a fixed-bearing prosthesis that reduces knee pain dramatically and may last for many years. Knee prostheses consist of three component parts that function together as a system:
- Femoral: a polished, strong metal shell on the lower end of the thighbone.
- Tibial: a high-density polyethylene piece on top of a metal tray.
- Patellar: a high-density polyethylene piece replacing the underside of the kneecap in the center of the knee.
In certain cases, excessive activity and extra weight can accelerate the process of wear to parts of a fixed-bearing prosthesis, causing it to loosen from the bone and become painful. Loosening is a major reason some artificial joints fail.
If you are younger, more active and/or overweight, sometimes a doctor may recommend a rotating platform/mobile-bearing knee replacement designed for potentially longer performance with less wear. Doctors also consider gender, occupation, disability level, pain intensity, interference with lifestyle and other medical conditions in selecting the appropriate prosthesis.
Difference is bearing surface
Like fixed-bearing replacements, mobile-bearing knees use three components to provide a relatively natural and even interface. The difference is the bearing surface. In a mobile-bearing knee replacement, both the metallic femoral component and metallic tibial tray move across a polyethylene insert to create a dual-surface articulation. The insert absorbs forces across a larger contact surface, helping reduce the amount of wear to the bearing and loosening in places where the prosthesis attaches to bone.
Advantages: Mobile-bearing knee replacements can reduce early wear failure caused by high contact stress and early loosening failure caused by over-constraint. The insert's mobility ensures congruent contact between the femoral and tibial components and conformity of the surfaces that move together when you bend and rotate your knee during activity. The mobile-bearing insert lets you move the knee from both the thighbone and shinbone. You can also rotate the shinbone slightly.
Disadvantages: Compared with fixed-bearing designs, mobile-bearing knee implants are less forgiving of imbalance in soft tissues. They may increase the chance of dislocation and may cost more than fixed-bearing implants.
Runner's Knee (Patellofemoral Pain)
Runners, jumpers and other athletes such as skiers, cyclists and soccer players put heavy stress on their knees. "Runner's knee" is a term some people use to refer to a number of medical conditions that can cause pain around the front of the knee (patellofemoral pain). These conditions include anterior knee pain syndrome, patellofemoral malalignment and chondromalacia patella.
Dull, aching pain under or around the front (anterior) of the kneecap-where the kneecap (patella) connects with the lower end of the thighbone (femur). It hurts to:
- Go up or down stairs
- Sit with the knee bent for long periods of time
The knee's complex structure is very sensitive. A number of factors can contribute to "runner's knee," including:
- The kneecap being out of alignment relative to the rest of the knee
- Excessive training or overuse
- Tightness, imbalance or weakness of thigh muscles
- Having flat feet
Stop doing any activities that hurt the knee, and don't start again until you can do them without any pain. This probably means stopping any running or jumping sports. Use the R.I.C.E. formula:
Rest: Avoid putting weight on the painful knee. Some athletes temporarily switch to a non-weight bearing activity, such as swimming.
Ice: Apply cold packs or ice wrapped in a towel for short periods of time, several times a day.
Compression: Use an elastic bandage such as a simple knee sleeve with the kneecap cut out that fits snugly without causing pain.
Elevation: Keep the knee raised up higher than your heart.
Take nonsteroidal anti-inflammatory medications such as aspirin or ibuprofen if you need more pain relief. If your knee does not improve with rest, see your doctor for complete medical evaluation and diagnosis. "Runner's knee" usually gets better with early treatment and reconditioning.
Tell your doctor your complete medical history. He or she will physically examine your knee and may order X-rays or other diagnostic tests to help determine the cause of pain.
Medical history. Describe your symptoms. When did knee pain start? Tell the doctor about any sports participation or training you are involved in, and which activities aggravate your knee. Have there been any recent changes to the duration, frequency or intensity of your activities? Any changes to the surfaces you run or play upon?
Physical exam. To assess your knee's strength, mobility and alignment, the doctor may ask you to stand, walk or jump, squat, sit and lie down. He or she may check alignment of the lower leg, kneecap and quadriceps; knee stability, hip rotation and range of motion of knees and hips; under the kneecap for signs of tenderness; the attachment of thigh muscles to the kneecap; strength, flexibility, firmness, tone and circumference of quadriceps and hamstring muscles; tightness of the heel cord and flexibility of the feet.
Diagnostic tests. In some cases, the doctor may need to rule out damage to the structure of the knee and the tissues that connect to it. He or she may order diagnostic tests such as X-rays, MRIs (magnetic resonance imaging studies), CT (computed tomography) scans and blood tests.
Patellofemoral pain may be the result of irritation in the soft tissues around the front of the knee. Strained tendons are fairly common in athletes. Pain that begins in another part of the body, such as the back or hip, may cause pain in the knee (referred pain). In some cases, the kneecap may be out of alignment. If so, vigorous activities can cause excessive stress and wear on the cartilage of the kneecap. This can lead to the cartilage softening and breaking down (chondromalacia of the patella), and cause pain in the underlying bone and irritation of the joint lining.
Treatment and reconditioning
Treatment depends upon the particular problem causing knee pain, and is usually non-surgical. After resting the knee until pain and swelling go down, you may need reconditioning to regain full range of motion, strength, power, endurance, speed, agility and coordination. Your doctor may prescribe an exercise program to normalize the flexibility and strength of thigh muscles, or recommend cross training exercises that emphasize stretching the lower extremities. Your doctor will tell you when you may gradually resume running and other sports activities.
Other non-surgical treatments involve taping the kneecap or using a special brace for knee support during sports participation. Special shoe inserts (orthotics) may sometimes be prescribed and help the pain go away.
When needed, surgical treatments include:
- Arthroscopy: The surgeon removes fragments of damaged kneecap cartilage through a small incision, using a pencil-sized instrument (arthroscope).
- Realignment: The surgeon opens the knee structure and realigns the kneecap, reducing abnormal pressure on cartilage and supporting structures around the front of the knee.
To avoid knee pain:
- Stay in shape. Good general conditioning is important to controlling or preventing patellofemoral pain. If you're too heavy, you may need to lose weight to avoid overstressing your knees. Before running or any other exercise, first do a five-minute warm up, followed by stretching exercises.
- Stretch. Stretching, particularly in the face down position (prone), will help keep flexible the supporting structures around the front of the knee, and make them less likely to be irritated with exercise. For example: when lying prone, grab the ankle of the affected leg with one hand, and gently stretch the front of the knee. Stretch before and after exercise.
- Increase training gradually. Avoid sudden changes in the intensity of exercise. Increase force or duration of activities gradually.
- Use proper running gear. Use running shoes with good shock absorption and quality construction. Be sure shoes fit properly and are in good condition. If you have flat feet, you may need shoe inserts.
- Use proper running form. Lean forward and keep the knees bent. Also, try to run on a clear, smooth, resilient, even and reasonably soft surface. Never run straight down a steep hill. Walk down it, or run in a zigzag pattern.
Surgical Treatment of Osteoarthritis of the Knee
The first line of treatment for osteoarthritis of the knee (OA Knee) is nonsurgical. However, if conservative treatment does not relieve pain and improve function, your physician may recommend surgery. About one in four people with OA Knee will eventually need surgery. The choice of treatment should be a joint decision between you and your physician.
The purpose of surgical treatment for OA Knee is to reduce pain, increase function and improve your symptoms overall. Patient satisfaction is a fundamental goal in treating OA Knee. Surgical treatments options include:
Arthroscopy is a surgical procedure that uses small incisions and miniature instruments. A tiny telescope (arthroscope) is inserted into the joint space, which is then filled with fluids so the surgeon can clearly see the components of the joint. This enables the surgeon to look directly at the bone surfaces and to determine how advanced your arthritis is.
Using tiny instruments, the surgeon can trim damaged cartilage, remove any loose particles or debris from the joint (a procedure called debridement) and clean the joint (a process called "lavage" or "irrigation"). If other problems are discovered, such as a torn meniscus (a C-shaped piece of cushioning in the knee) or a damaged ligament, they can be corrected during the same surgery.
Arthroscopy can be helpful if your joint pain results from a tear in the cartilage or meniscus, or if bits of debris are causing problems in bending or straightening the joint. In people under age 55, arthroscopic surgery may help delay the need for more serious surgery such as a joint replacement. As with any surgery, there are some risks due to the use of anesthesia and the possibility of infection. Other complications may include damage to nerves or blood vessels, the development of blood clots in veins and scarring.
Arthroscopy is not the best option for everyone. Although the puncture wounds are small and pain is minimal, it takes several weeks for the joint to recover fully. Your physician will prescribe a specific activity and rehabilitation program to encourage recovery and protect future function of the joint.
An osteotomy may be recommended if damage to your knee cartilage is primarily in one section (compartment) of the knee. The inside (medial) compartment, where the inner knob of the thighbone (femoral condyle) meets the top of the shinbone (tibia), is most commonly involved. An osteotomy also may be recommended if a broken knee does not heal properly. This procedure involves reshaping the bones to improve knee alignment. The surgeon repositions the joint to move the mechanical axis of weightbearing for the limb away from the damaged area. This shifts weightbearing stresses from the damaged section to a healthier part of the knee. An osteotomy can restore knee function and diminish osteoarthritis pain. It may even stimulate the growth of new cartilage. Although an osteotomy can decrease pain and improve function, the results often deteriorate over the long term. Many people who have an osteotomy will eventually need a total knee replacement (arthroplasty). As with all surgeries, there is a slight possibility of infection, complications from the anesthesia or other surgical complications such as blood clots, nerve damage and circulation problems. There will be a cosmetic difference between the surgically-treated knee and the untreated knee.
An arthroplasty is a joint replacement procedure. If your OA Knee pain is severe and significantly limits your movement, your physician may recommend that the diseased bone and tissue be replaced by an artificial joint. If your arthritis is localized to one side of the knee, your orthopaedic surgeon may recommend a unicompartmental knee arthroplasty. If both sides of the knee are affected, a total joint replacement may be more appropriate. The replacment parts are made of cobalt-chrome or titanium metals and smooth, wear-resistant plastic (polyethylene).
The results of total joint replacement are generally excellent. Patients experience significant pain relief and improved physical functioning. There are some risks to the surgery, and full rehabilitation may take three to six months. In addition, the prosthesis (artificial joint) may eventually loosen or wear out so that a second surgery is needed. However, at the 10-year mark, the success rate with most prostheses today is about 90 percent.
Your orthopaedic surgeon should discuss the type of knee replacement, the type of surgery (minimal incision or standard incision), the potential risks and the rehabilitation protocol with you before you make your decision.
The Impact of Osteoarthritis of the Knee
Osteoarthritis of the knee (OA Knee) is a leading cause of physical disability. Generally, adults who have OA Knee report having some pain, stiffness or swelling in the knee joint on most days. OA Knee, along with osteoarthritis of the hip, has a major effect on a person's ability to walk and climb stairs. Here are some frequently asked questions about OA Knee and its effect on a person's life.
Who is affected by OA Knee?
In 2001, more than 13.5 million American adults reported having knee joint pain, swelling and stiffness. Among those with OA Knee, almost half are older than 65 years of age. Among those in the United States who say they have OA Knee, 88 percent are white and 9 percent are African-Americans.
How many visits did people make to a doctor's office for OA Knee?
In 2001, people with OA Knee made more than 5.5 million visits to physicians' offices and more than 271,000 outpatient visits for a variety of reasons.
How many hospitalizations are there for OA Knee?
There were between 400,000 and 458,000 inpatient hospital stays for individuals with OA Knee in 1999 (counting all hospital visits for all reasons).
- The average length of stay for these patients was almost five days.
- The average charge per hospital stay was $23,746.
- About one in five OA Knee patients, regardless of the reason for their hospitalization, went to a skilled nursing facility or nursing home after being released from the hospital.
- In 1999, about 25 percent of all adults with OA Knee had some type of surgery. The procedure most frequently performed for patients with OA Knee is a total knee joint replacement.
What impact does OA Knee have on a person's physical and mental well-being?
- More than 40 percent of people with OA Knee rate their health as "poor" or "fair."
- Almost 28 percent expect that it is "definitely" or "mostly" true that their health will get worse.
- When adults with OA Knee were asked how they felt all or most of the time during the previous month, about 13 percent reported "everything is an effort."
- In general, people with OA Knee report a higher degree of emotional distress than adults without arthritis or other health limitations.
What impact does OA Knee have on daily living activities?
- In 1999, about 50 percent of adults with OA Knee were "unable" or had "much difficulty" crouching, stooping or kneeling.
- More than 30 percent of adults with OA Knee were "unable" or had "much difficulty" in walking a quarter of a mile; more than one-fourth were unable to take 10 steps without resting.
- More than 25 percent were "unable" or had "much difficulty" in lifting or carrying 10 pounds.
- In contrast, less than 1 percent of adults without OA Knee had difficulties in these areas.
What impact does OA Knee have on work attendance?
In 1999, adults with OA Knee reported that they missed an average of more than 13 days of work for health reasons in the previous year. They also spent an average of almost 18 days in bed because of health reasons. People without OA knee, however, missed only about three days of work and spent one-and-a-half days in bed for health reasons during the year.
About 19.4 million visits were made to physicians' offices in 2003 because of a knee problem (Source: National Center for Helath Statistics; Centers for Disease Control and Prevention; 2003 National Ambulatory Medical Care Survey.) It was the most common reason for visiting orthopaedic surgeons.
There are many components to the knee making it vulnerable for various types of injuries. Many injuries are successfully treated conservatively, while others require surgery to correct. Here are some facts about the knee from the American Academy of Orthopaedic Surgeons.
How does the knee work?
The knee is the largest joint in the body, and one of the most easily injured. It is made up of the lower end of the thighbone (femur) which rotates on the upper end of the shinbone (tibia), and the knee cap (patella) which slides in a groove on the end of the femur. The knee also contains large ligaments which help control motion by connecting bones and bracing the joint against abnormal types of motion. Other parts of your knee, like cartilage, serve to cushion your knee or help it absorb shock during motion.
What are the most prevalent knee injuries?
Many athletes experience injuries to their knee ligaments. Of the four major ligaments found in the knee, the anterior cruciate ligament (ACL) and the medial collateral ligament (MCL) often are injured in sports. The posterior cruciate ligament (PCL) also is frequently injured.
Changing or twisting direction rapidly, slowing down when running, and landing from a jump are often the causes of tears in the ACL. Athletes participating in skiing and basketball and athletes wearing cleated shoes, such as football players, are susceptible to ACL injuries.
Injuries to the MCL usually are caused by contact on the outside of the knee. These types of blows to the knee often are encountered in contact sports such as football.
The PCL can be injured during a sports activity when the athlete receives a blow to the front of the knee or makes a simple misstep on the playing field. Athletes engaging in contact sports such as football or soccer are susceptible to a PCL injury.
Other than ligament injuries, are there any other types of injuries?
Torn knee cartilage is experienced by many people. When people talk about torn knee cartilage, they usually are referring to a torn meniscus. The mensicus is a tough, rubbery cartilage that is attached to the knee's ligaments. It acts like a shock absorber.
In athletic activities, mensicus tears usually occur when twisting, cutting, pivoting, decelerating, or being tackled. Direct contact is often involved.
How are knee injuries treated?
There are a variety of methods used by orthopaedic surgeons to treat knee injuries in athletes. The most important advice is to seek treatment as soon as possible. A common method used by orthopaedic surgeons to treat mild knee injuries is R.I.C.E.-rest, ice, compression, and elevation. Rest the knee by staying off it or walking only with crutches. Apply ice to control swelling. Use a compressive elastic bandage applied snugly but loosely enough so that it does not cause pain. Finally, keep the knee elevated.
Total Knee Replacement
If your knee is severely damaged by arthritis or injury, it may be hard for you to perform simple activities such as walking or climbing stairs. You may even begin to feel pain while you're sitting or lying down.
If medications, changing your activity level and using walking supports are no longr helpful, you may want to consider total knee replacement surgery. By resurfacing your knee's damaged and worn surfaces, total knee replacement surgery can relieve your pain, correct your leg deformity and help you resume your normal activities.
One of the most important orthopaedic surgical advances of the twentieth century, knee replacement was first performed in 1968. Improvements in surgical materials and techniques since then have greatly increased its effectiveness. Approximately 300,000 knee replacements are performed each year in the United States.
Whether you have just begun exploring treatment options or have already decided with your orthopaedic surgeon to have total knee replacement surgery, this booklet will help you understand more about this valuable procedure.
How the Normal Knee Works
The knee is the largest joint in the body. Nearly normal knee function is needed to perform routine everyday activities. The knee is made up of the lower end of the thigh bone (femur), which rotates on the upper end of the shin bone (tibia), and the knee cap (patella), which slides in a groove on the end of the femur. Large ligaments attach to the femur and tibia to provide stability. The long thigh muscles give the knee strength.
The joint surfaces where these three bones touch are covered with articular cartilage, a smooth substance that cushions the bones and enables them to move easily.
All remaining surfaces of the knee are covered by a thin, smooth tissue liner called the synovial membrane. This membrane releases a special fluid that lubricates the knee, reducing friction to nearly zero in a healthy knee.
Normally, all of these components work in harmony. But disease or injury can disrupt this harmony, resulting in pain, muscle weakness and less function.
Common Causes of Knee Pain and Loss of Knee Function
The most common cause of chronic knee pain and disability is arthritis. Osteoarthritis, rheumatoid arthritis and traumatic arthritis are the most common forms.
Osteoarthritis usually occurs after the age of 50 and often in an individual with a family history of arthritis. The cartilage that cushions the bones of the knee softens and wears away. The bones then rub against one another, causing knee pain and stiffness.
Rheumatoid Arthritis is a disease in which the synovial membrane becomes thickened and inflamed, producing too much synovial fluid that over-fills the joint space. This chronic inflammation can damage the cartilage and eventually cause cartilage loss, pain and stiffness.
Traumatic Arthritis can follow a serious knee injury. A knee fracture or severe tears of the knee's ligaments may damage the articular cartilage over time, causing knee pain and limiting knee function.
Is Total Knee Replacement for You?
The decision whether to have total knee replacement surgery should be a cooperative one between you, your family, your family physician and your orthopaedic surgeon. Your physician may refer you to an orthopaedic surgeon for a thorough evaluation to determine if you could benefit from this surgery. Alternatives to traditional total knee replacement surgery that your orthopaedic surgeon may discuss with you include a unicompartmental knee replacement or a minimally invasive knee replacement.
Reasons that you may benefit from total knee replacement commonly include:
- Severe knee pain that limits your everyday activities, including walking, going up and down stairs, and getting in and out of chairs. You may find it hard to walk more than a few blocks without significant pain and you may need to use a cane or walker.
- Moderate or severe knee pain while resting, either day or night
- Chronic knee inflammation and swelling that doesn't improve with rest or medications
- Knee deformity--a bowing in or out of your knee
- Knee stiffness--inability to bend and straighten your knee
- Failure to obtain pain relief from non-steroidal anti-inflammatory drugs. These medications, including aspirin and ibuprofen, often are most effective in the early stages of arthritis. Their effectiveness in controlling knee pain varies greatly from person to person. These drugs may become less effective for patients with severe arthritis.
- Inability to tolerate or complications from pain medications
- Failure to substantially improve with other treatments such as cortisone injections, physical therapy, or other surgeries
Most patients who undergo total knee replacement are age 60 to 80, but orthopaedic surgeons evaluate patients individually. Recommendations for surgery are based on a patient's pain and disability, not age. Total knee replacements have been performed successfully at all ages, from the young teenager with juvenile arthritis to the elderly patient with degenerative arthritis.
The Orthopaedic Evaluation
The orthopaedic evaluation consists of several components:
- A medical history, in which your orthopaedic surgeon gathers information about your general health and asks you about the extent of your knee pain and your ability to function
- A physical examination to assess your knee motion, stability, strength and overall leg alignment
- X-rays to determine the extent of damage and deformity in your knee
- Occasionally blood tests, a Magnetic Resonance Image (MRI) or a bone scan may be needed to determine the condition of the bone and soft tissues of your knee.
Your orthopaedic surgeon will review the results of your evaluation with you and discuss whether total knee replacement would be the best method to relieve your pain and improve your function. Other treatment options--including medications, injections, physical therapy, or other types of surgery--also will be discussed and considered.
Your orthopaedic surgeon also will explain the potential risks and complications of total knee replacement, including those related to the surgery itself and those that can occur over time after your surgery.
Realistic Expectations About Knee Replacement Surgery
An important factor in deciding whether to have total knee replacement surgery is understanding what the procedure can and can't do.
More than 90 percent of individuals who undergo total knee replacement experience a dramatic reduction of knee pain and a significant improvement in the ability to perform common activities of daily living. But total knee replacement won't make you a super-athlete or allow you to do more than you could before you developed arthritis.
Following surgery, you will be advised to avoid some types of activity, including jogging and high impact sports, for the rest of your life.
With normal use and activity, every knee replacement develops some wear in its plastic cushion. Excessive activity or weight may accelerate this normal wear and cause the knee replacement to loosen and become painful. With appropriate activity modification, knee replacements can last for many years.
Preparing for Surgery
If you decide to have total knee replacement surgery, you may be asked to have a complete physical by your family physician several weeks before surgery to assess your health and to rule out any conditions that could interfere with your surgery.
Several tests-such as blood samples, a cardiogram and a urine sample-may be needed to help your orthopaedic surgeon plan your surgery.
Preparing Your Skin and Leg
Your knee and leg should not have any skin infections or irritation. Your lower leg should not have any chronic swelling. Contact your orthopaedic surgeon prior to surgery if either of these conditions is present for a program to best prepare your skin for surgery.
You may be advised to donate your own blood prior to the surgery. It will be stored in the event you need blood after your surgery.
Tell your orthopaedic surgeon about the medications you are taking. He or she will tell you which medications you should stop taking and which you should continue to take before surgery.
Although the incidence of infection after knee replacement is very low, an infection can occur if bacteria enter your bloodstream. Treatment of significant dental diseases (including tooth extractions and periodontal work) should be considered before your total knee replacement surgery.
A preoperative urological evaluation should be considered for individuals with a history of recent or frequent urinary infections. For older men with prostate disease, required treatment should be considered prior to knee replacement surgery.
Though you will be able to walk on crutches or a walker soon after surgery, you will need help for several weeks with such tasks as cooking, shopping, bathing and doing laundry. If you live alone, your surgeon's office and a social worker or a discharge planner at the hospital can help you make advance arrangements to have someone assist you at home. They also can help you arrange for a short stay in an extended care facility during your recovery, if this option works best for you.
Several suggestions can make your home easier to navigate during your recovery. Consider:
Safety bars or a secure handrail in your shower or bath
Secure handrails along your stairways
A stable chair for your early recovery with a firm seat cushion (height of 18-20 inches), a firm back, two arms, and a footstool for intermittent leg elevation
A toilet seat riser with arms, if you have a low toilet
A stable shower bench or chair for bathing
Removing all loose carpets and cords
A temporary living space on the same floor, because walking up or down stairs will be more difficult during your early recovery
You will most likely be admitted to the hospital on the day of your surgery. After admission, you will be evaluated by a member of the anesthesia team. The most common types of anesthesia are general anesthesia, in which you are asleep throughout the procedure, and spinal or epidural anesthesia, in which you are awake but your legs are anesthetized. The anesthesia team will determine which type of anesthesia will be best for you with your input.
The procedure itself takes about two hours. Your orthopaedic surgeon will remove the damaged cartilage and bone and then position the new metal and plastic joint surfaces to restore the alignment and function of your knee.
Many different types of designs and materials are currently used in total knee replacement surgery. Nearly all of them consist of three components: the femoral component (made of a highly polished strong metal), the tibial component (made of a durable plastic often held in a metal tray), and the patellar component (also plastic).
After surgery, you will be moved to the recovery room, where you will remain for one to two hours while your recovery from anesthesia is monitored. After you awaken, you will be taken to your hospital room.
Unicompartmental Knee Replacement
Although not as common as total knee replacement, the partial or unicompartmental knee replacement is a viable alternative in limited situations. The designs of the unicompartmental types of knee replacements have improved over the years, as has the sophistication of the instruments used to implant these types of artificial joints. The unicompartmental knee replacement also has smaller, less invasive incisions.
The "uni," as it is commonly called, is used to replace a single compartment of the arthritic knee. The knee joint has three compartments: the medial (inner) compartment, the lateral (outer) compartment and the patellofemoral (kneecap) compartment. If the damage is limited to either the medial or lateral compartment, that compartment may be replaced with the uni.
If two or more compartments are damaged, the uni may not be the best option. The uni is also less desireable for a young, active person because it may not withstand the extremes of stress that high levels of activity create. It is best suited for the older, slim person with a relatively sedentary lifestyle. Only between six and eight out of 100 patients with arthritic knees are good candidates for a unicompartmental knee replacement.
Because the uni can be inserted through a relatively small incision (about 3" or 4" long), which does not interrupt the main muscle controling the knee, rehabilitation is faster, hospitalization is shorter and return to normal activities is more rapid than after a total knee replacement.
However, this is still a serious operation, which has all the same risks as total knee replacement. These risks, as well as whether you are a good candidate for the uni, should be discussed with your orthopaedic surgeon.
Minimally Invasive Knee Replacement
A recent advance in the performance of total knee replacement is the use of minimally invasive approaches. This technique, still in its relative infancy, is more challenging than standard total knee replacement. The incisions are approximately half the size of those used in a standard approach. The smaller incisions and new techniques to expose the joint may result in short-term advantages such as a quicker rehabilitation, possibly less pain and a shorter hospitalization, according to some reports.
The minimally invasive approach to the total knee replacement is appropriate for non-obese patients who have reasonable motion without significant deformity. Hospitalization may be reduced to one to three days among these patients, and the need for an extended stay for inpatient rehabilitation may be reduced or eliminated in most patients.
Although some studies show shorter hospitalizations and rehabilitation periods, other studies find minimally invasive surgery to be no better than standard techniques. The risks are not well known, but are probably comparable to those for a standard total knee replacement. Speak to your orthopaedic surgeon about whether you might be an appropriate candidate for this particular approach to total knee replacement.
Your Stay in the Hospital
You will most likely stay in the hospital for several days. After surgery, you will feel some pain, but medication will be given to you to make you feel as comfortable as possible. Pain management is an important part of your recovery, so talk with your surgeon if postoperative pain becomes a problem. Walking and knee movement are important to your recovery and will begin immediately after your surgery.
To avoid lung congestion after surgery, you should breathe deeply and cough frequently to clear your lungs.
Your orthopaedic surgeon may prescribe one or more measures to prevent blood clots and decrease leg swelling, such as special support hose, inflatable leg coverings (compression boots) and blood thinners.
To restore movement in your knee and leg, your surgeon may use a knee support that slowly moves your knee while you are in bed. The device, called a continuous passive motion (CPM) machine, decreases leg swelling by elevating your leg and improves your venous circulation by moving the muscles of your leg.
Foot and ankle movement also is encouraged immediately following surgery to increase blood flow in your leg muscles to help prevent leg swelling and blood clots. Most patients begin exercising their knee the day after surgery. A physical therapist will teach you specific exercises to strengthen your leg and restore knee movement to allow walking and other normal daily activities soon after your surgery.
Possible Complications After Surgery
The complication rate following total knee replacement is low. Serious complications, such as a knee joint infection, occur in less than 2 percent of patients. Major medical complications such as heart attack or stroke occur even less frequently. Chronic illnesses may increase the potential for complications. Although uncommon, when these complications occur, they can prolong or limit your full recovery.
Blood clots in the leg veins are the most common complication of knee replacement surgery. Your orthopaedic surgeon will outline a prevention program, which may include periodic elevation of your legs, lower leg exercises to increase circulation, support stockings and medication to thin your blood.
Although implant designs and materials as well as surgical techniques have been optimized, wear of the bearing surfaces or loosening of the components may occur. Additionally, although an average of 115 degrees of motion is generally anticipated after surgery, scarring of the knee can occasionally occur and motion may be more limited. This is particularly true in patients with limited motion before surgery. Finally, while rare, injury to the nerves or blood vessels around the knee can occur during surgery.
Discuss your concerns thoroughly with your orthopaedic surgeon prior to surgery.
Your Recovery at Home
The success of your surgery also will depend on how well you follow your orthopaedic surgeon's instructions at home during the first few weeks after surgery.
You will have stitches or staples running along your wound or a suture beneath your skin on the front of your knee. The stitches or staples will be removed several weeks after surgery. A suture beneath your skin will not require removal.
Avoid soaking the wound in water until the wound has thoroughly sealed and dried. The wound may be bandaged to prevent irritation from clothing or support stockings.
Some loss of appetite is common for several weeks after surgery. A balanced diet, often with an iron supplement, is important to promote proper tissue healing and restore muscle strength.
Exercise is a critical component of home care, particularly during the first few weeks after surgery. You should be able to resume most normal activities of daily living within three to six weeks following surgery. Some pain with activity and at night is common for several weeks after surgery. Your activity program should include:
- A graduated walking program to slowly increase your mobility, initially in your home and later outside
- Resuming other normal household activities, such as sitting and standing and walking up and down stairs
- Specific exercises several times a day to restore movement and strengthen your knee. You probably will be able to perform the exercises without help, but you may have a physical therapist help you at home or in a therapy center the first few weeks after surgery.
Driving usually begins when your knee bends sufficiently so you can enter and sit comfortably in your car and when your muscle control provides adequate reaction time for braking and acceleration. Most individuals resume driving about four to six weeks after surgery.
Avoiding Problems After Surgery
Blood Clot Prevention
Follow your orthopaedic surgeon's instructions carefully to minimize the potential of blood clots that can occur during the first several weeks of your recovery.
Warning signs of possible blood clots in your leg include:
- Increasing pain in your calf
- Tenderness or redness above or below your knee
- Increasing swelling in your calf, ankle and foot
Warning signs that a blood clot has traveled to your lung include:
- Sudden increased shortness of breath
- Sudden onset of chest pain
- Localized chest pain with coughing
Notify your doctor immediately if you develop any of these signs.
The most common causes of infection following total knee replacement surgery are from bacteria that enter the bloodstream during dental procedures, urinary tract infections, or skin infections. These bacteria can lodge around your knee replacement and cause an infection.
For the first two years after your knee replacement, you must take preventive antibiotics before dental or surgical procedures that could allow bacteria to enter your bloodstream. After two years, talk to your orthopaedist and your dentist or urologist to see if you still need preventive antibiotics before any scheduled procedures.
Warning signs of a possible knee replacement infection are:
- Persistent fever (higher than 100 degrees orally)
- Shaking chills
- Increasing redness, tenderness or swelling of the knee wound
- Drainage from the knee wound
- Increasing knee pain with both activity and rest
Notify your doctor immediately if you develop any of these signs.
A fall during the first few weeks after surgery can damage your new knee and may result in a need for further surgery. Stairs are a particular hazard until your knee is strong and mobile. You should use a cane, crutches, a walker, hand rails or someone to help you until you have improved your balance, flexibility and strength.
Your surgeon and physical therapist will help you decide what assistive aides will be required following surgery and when those aides can safely be discontinued.
How Your New Knee Is Different
You may feel some numbness in the skin around your incision. You also may feel some stiffness, particularly with excessive bending activities. Improvement of knee motion is a goal of total knee replacement, but restoration of full motion is uncommon. The motion of your knee replacement after surgery is predicted by the motion of your knee prior to surgery. Most patients can expect to nearly fully straighten the replaced knee and to bend the knee sufficiently to go up and down stairs and get in and out of a car. Kneeling is usually uncomfortable, but it is not harmful. Occasionally, you may feel some soft clicking of the metal and plastic with knee bending or walking. These differences often diminish with time and most patients find these are minor, compared to the pain and limited function they experienced prior to surgery.
Your new knee may activate metal detectors required for security in airports and some buildings. Tell the security agent about your knee replacement if the alarm is activated.
After surgery, make sure you also do the following:
Participate in regular light exercise programs to maintain proper strength and mobility of your new knee.
Take special precautions to avoid falls and injuries. Individuals who have undergone total knee replacement surgery and suffer a fracture may require more surgery.
Notify your dentist that you had a knee replacement. You should be given antibiotics before all dental surgery for the rest of your life.
See your orthopaedic surgeon periodically for a routine follow-up examination and X-rays, usually once a year.
Your orthopaedic surgeon is a medical doctor with extensive training in the diagnosis and nonsurgical and surgical treatment of the musculoskeletal system, including bones, joints, ligaments, tendons, muscles and nerves.
When things are "in the groove," they're going smoothly. That certainly is the case with your knee. As long as your kneecap (patella) stays "in the groove," you can walk, run, sit, stand and move easily. When the kneecap slips out of the groove, problems and pain often result.
The kneecap connects all the muscles in the thigh to the shinbone (tibia). As you bend or straighten your leg, the kneecap is pulled up or down. The thighbone (femur) has a V-shaped notch (femoral groove or sulcus) at one end to accommodate the moving kneecap. In a normal knee, the kneecap fits nicely in the groove. But if the groove is uneven or too shallow, the kneecap could slide off, resulting in a partial or complete dislocation. A sharp blow to the kneecap, as in a fall, could also pop the kneecap out of place.
- Knee buckles and can no longer support your weight.
- Kneecap slips off to the side.
- Pain in the front of the knee increases with activity.
- Creaking or cracking sounds during movement.
During the examination, your doctor may ask you to walk around or to straighten and bend your knee. He or she may carefully feel the area around the kneecap and take measurements to determine if the bones are out of alignment or if the thigh muscles are weak. X-rays may be recommended to see how the kneecap fits in its groove. Your doctor will also want to eliminate other possible reasons for the pain, such as a tear in the cartilage or ligaments of the knee.
If the kneecap has popped totally out of its groove (dislocated), the first step is to return it to its proper place. This process is called reduction. Sometimes this happens spontaneously; other times, your doctor will have to apply gentle force to push the kneecap back in place. A dislocation often damages the underside of the kneecap and the end of the thighbone, which can lead to additional pain and arthritis. Arthroscopic surgery can correct this condition.
If the kneecap is only partially off track (subluxated), your doctor may recommend nonoperative treatments, such as exercises and braces. Exercises will help strengthen the muscles in your thighs so that the kneecap stays aligned.
Cycling is often recommended as part of the physical therapy. A stabilizing brace may also be prescribed. The goal is for you to return to your normal activities within one to three months.
A chronic condition, in which the knee continues to be unstable, can often be corrected by surgery. For example, surgery can be used to realign and tighten tendons to keep the kneecap on track, or to release tissues that pull the kneecap off track.
Viscosupplementation Treatment for Arthritis
A sticky or squeaking hinge can be "cured" with a drop of oil, so it makes sense that a hinge joint, like the knee, would also benefit from a little lubrication. At least that's the premise behind one new form of treatment for arthritis of the knee.
The procedure, called viscosupplementation, injects a preparation of hyaluronic acid into the knee joint. Hyaluronic acid is a naturally occurring substance found in the synovial (joint) fluid. It acts as a lubricant to enable bones to move smoothly over each other and as a shock absorber for joint loads.
However, people with osteoarthritis ("wear-and-tear" arthritis) have a lower-than-normal concentration of hyaluronic acid in their joints. Viscosupplementation may be a therapeutic option for individuals with osteoarthritis of the knee.
The first line of treatment for osteoarthritis of the knee aims to relieve pain. Normally, pain relievers such as ibuprofen or nonsteroidal anti-inflammatory drugs (NSAIDs) are used, along with physical therapy, applications of a topical analgesic and injections of a corticosteroid. However, some people have a reaction to NSAIDs and these agents usually bring only temporary relief. When conservative measures fail, surgery, perhaps even to replace the joint, may be required.
Viscosupplementation has been shown to relieve pain in many patients who did not get relief from nonmedicinal measures or analgesic drugs. The technique has been used in Europe and Asia for several years, but the U.S. Food and Drug Administration did not approve it until 1997, and then only for treating osteoarthritis of the knee. Two preparations of hyaluronic acid are available-a natural product made from rooster combs, and an artificial one manufactured from bacterial cultures. If you are allergic to egg or poultry products, the manufactured product should be used.
If there is any swelling (effusion) in the knee, your physician will remove (aspirate) the excess fluids before injecting the hyaluronic acid. Usually, this can be done at the same time, with only one needle injected into the joint, although some doctors may prefer to use two separate syringes. Depending on the product used, you will receive 3 to 5 shots over several weeks.
Effects of viscosupplementation
- Hyaluronic acid does not have an immediate pain-relieving effect.
- You may notice a local reaction, such as pain, warmth, and slight swelling immediately after the shot. These symptoms generally do not last long. You may want to apply an ice pack to help ease them.
- For the first 48 hours after the shot, you should avoid excessive weightbearing on the leg, such as standing for long periods, jogging or heavy lifting.
- Over the course of the injections, you may notice that you have less pain in your knee.
- Hyaluronic acid does seem to have anti-inflammatory and pain-relieving properties. The injections may also stimulate the body to produce more of its own hyaluronic acid.
Effects may last for several months.
Viscosupplementation doesn't work for everyone. There's no proof that it will reverse or delay the progress of osteoarthritis. In addition, it's very expensive and clinical trials have not yet proven that it is cost-effective.
If your current course of medication and treatment is working, stay with it. However, if your arthritis isn't responding well, or if you're trying to delay an inevitable surgery, you may wish to discuss this option with your orthopaedic surgeon.
Women and ACL Injuries
- For more than a decade, researchers have debated various reasons why anterior cruciate ligament (ACL) injuries are occurring more often in women than men, ranging from anatomical to hormonal differences in the genders.
- Recent studies show that female athletes participating in certain sports like soccer or basketball are three- to four-times more likely to injure their ACL than males. A majority of these injuries are occurring in women between the ages 15 and 25, it was reported at the meeting.
- At a June 1999 consensus meeting sponsored by the American Academy of Orthopaedic Surgeons, orthopaedic researchers reported these factors can explain the increase in ACL injuries among the female athletic population.
Biomechanical factors. Experts reported that females tend to place more emphasis on their quadriceps muscle than male athletes, making it a significant reason why they are at increased risk of ACL injuries. The panel agreed females should learn to use their hamstring muscles more often. The experts also concluded that females tend to land on a flat foot rather than their toes which can contribute to the increased injury rate.
Hormonal influences. There should be no modification of activity or restriction from a sport at any time during the menstrual cycle, experts said. They also stated that a woman's hormones do not increase the chances of sustaining an ACL injury, but suggested that further investigation is warranted.
Environmental factors. Functional knee braces do not prevent ACL injury, experts reported. They agreed that an athletic shoe's surface may improve performance because it provides good traction on certain surfaces, but at the same time increases the risk of injury.
Anatomic risk factors. The experts concluded that there were insufficient data to support the theory that ACL size is related to injury risk. They also reported that no consensus could be reached on the role of the size of the femoral notch (the area within the knee that contains the cruciate ligaments) as it relates to injury occurrence.
The researchers agreed training programs that teach proper landing methods or basic injury prevention techniques should be adopted to help female athletes.