The knee is the largest joint in the body and is central to nearly every routine activity. The knee joint is formed by the ends of 3 bones: the lower end of the thigh bone (femur), the upper end of the shin bone (tibia), and the knee cap (patella). Thick, tough tissue bands called ligaments connect the bones and stabilize the joint. A smooth, plastic-like lining called cartilage covers the ends of the bones and prevents them from rubbing against each other, allowing for flexible and nearly frictionless movement. Cartilage also serves as a shock absorber, cushioning the bones from the forces between them. Finally, a soft tissue called synovium lines the joint and produces a lubricating fluid that reduces friction and wear.
Normally, all of the parts of the knee joint work together and the joint moves easily and without pain. However, diseases or injury can disturb the normal functioning of the joint resulting in:
If non-invasive treatment options are not giving you satisfactory pain relief, knee surgery may become necessary. However, a total knee replacement (TKR) may not be necessary — alternate types of knee implants are available.