Total joint replacement is a surgical procedure in which certain parts of an arthritic or damaged joint, such as a hip or knee joint, are removed and replaced with a plastic or metal device called a prosthesis. The prosthesis is designed to enable the artificial joint to move just like a normal, healthy joint.
Hip replacement involves replacing the femur (head of the thigh bone) and the acetabulum (hip socket). Typically, the artificial ball with its stem is made of a strong metal, and the artificial socket is made of polyethylene (a durable plastic). In total knee replacement, the end of the femur (thigh bone) and the top of the tibia (shin bone) are resurfaced. The artificial knee implant is also composed of metal and polyethylene. The prosthesis is secured into place with bone cement or is covered with an advanced material that allows bone tissue to grow into it.
Total joint replacements of the hip and knee have been performed since the 1960s. Today, these procedures have been found to result in significant restoration of function and reduction of pain in 90% to 95% of patients.1 While the expected life of conventional joint replacements is difficult to estimate, it is not unlimited. Today’s patients can look forward to potentially benefiting from new advances that may increase the lifetime of hip and knee prostheses.
1. American Academy of Orthopaedic Surgeons website, accessed January 2009.