Sometimes the forces and load on the knee are uneven. Only one side or the other of the joint gets worn down. Arthritis affecting only the medial (inside) or lateral (outside) edge of the joint can be treated with a unicompartmental knee replacement (UKR).

With a UKR, the other parts of the knee and knee ligaments are mostly untouched by the operation. Knee motion is nearly normal after this surgery.

The first criterion for UKR is unilateral arthritis. Since a total knee replacement is not advised in young or middle-aged patients, the UKR is a possible choice for this patient group.

At the present time, the knee ligaments must be stable before a UKR can be implanted. You may be a candidate for UKR if you have both unilateral joint disease and intact ligaments.