Total knee replacement is indicated for end-stage degeneration of the knee joint with loss of articular (joint surface) cartilage. The most common reasons for this operation are osteoarthritis (idiopathic or post-traumatic) and inflammatory arthritis (rheumatoid, psoriatic, etc.). Total knee replacement is typically considered once all other conservative modalities (oral medications, intra-articular injections, physical therapy, weight loss, etc.) have failed to relieve the pain and dysfunction associated with knee degeneration.

The natural knee joint consists of three compartments: lateral, medial, and patellofemoral. A total knee replacement is designed to resurface the damaged articular surfaces of these compartments. Both the femoral and tibial components are typically made from metal. A high-density plastic (polyethylene) insert is placed between the metal components to serve as the artificial cartilage of the joint. Highly crosslinked polyethylene may be utilized as a more wear-resistant bearing surface; however, long-term results with this type of plastic are not yet available. Most total knee replacements also resurface the patella with an all-polyethylene component. Fixation of the metal components to the bone is typically done with bone cement, but some designs allow for fixation by bony ingrowth into porous metal surfaces applied to the surface of the implant, which is placed against the bone. By removing all damaged surfaces of the knee, pain can be alleviated and function restored.