Knee Replacement

About Knee Replacement

Total knee arthroplasty resurfaces the damaged ends of the femur and tibia, and often the undersurface of the patella, with metal and plastic components. It is among the most common joint replacement operations. End stage osteoarthritis is the leading indication, with others including rheumatoid arthritis, post traumatic arthritis and avascular necrosis. A polyethylene insert sits between the metal femoral and tibial components and acts as the bearing surface. Most components are fixed with bone cement, although cementless designs are also used. The two main design families are cruciate retaining implants, which keep the posterior cruciate ligament, and posterior stabilized implants, which replace its function with a cam and post mechanism. Partial or unicompartmental knee replacement is an option when arthritis is confined to one part of the joint. Computer navigation, patient specific instruments and robotic systems aim to improve alignment and implant positioning. Rehabilitation with physical therapy begins early, and improvement in pain and function continues for many months. Complications include infection, which may require staged revision, stiffness sometimes treated with manipulation under anesthesia, instability, loosening, blood clots and fracture around the implant. Long term implant survival is generally high, although a minority of patients remain dissatisfied with the result.