A partial knee replacement is an alternative to total knee replacement for some people with osteoarthritis of the knee. This surgery can be done when the damage is confined to a particular compartment of the knee. In a partial knee replacement, only the damaged part of the knee cartilage is replaced with a prosthesis.
Once partial knee replacement was reserved for older patients who were involved in few activities. Now partial knee replacement is often done in younger people as their recovery is quicker and usually less painful. About 5% to 6% of people with arthritic knees are estimated to be eligible for partial knee replacement.
People with medial, or lateral, knee osteoarthritis can be considered for partial knee replacement. "Medial" refers to the inside compartment of the joint, which is the compartment nearest the opposite knee, while "lateral" refers to the outside compartment farthest from the opposite knee. Medial knee joint degeneration is the most common deformity of arthritis.
Compared to total knee replacement, partial knee replacement better preserves range of motion and knee function because it preserves healthy tissue and bone in the knee. For these reasons, patients tend to be more satisfied with partial knee replacement compared with total knee replacement. They are still candidates for total knee replacement should they ever need it in the future.
There is also less blood loss during surgery, and knee motion recovers faster with partial knee replacement.