When patients with arthritis have pain that can no longer be controlled with medicine or injections, thoughts of surgery in the form of knee replacement come up. In some cases there is arthritis primarily in one area of the knee. These patients may be candidates for a partial knee replacement. In terms of arthritis, the knee is considered to have three main areas, the inner or medial compartment, the outer or lateral compartment, and the kneecap area or patellofemoral compartment. There are partial replacements for each of these areas or compartments.
Partial knee replacements have some advantages and disadvantages when compared to a total knee replacement (all three compartments). A partial replacement can recover more quickly because it is less surgery. It can feel more natural because it retains more of the patient’s own knee. Its main disadvantages are that it will not treat arthritis if it develops in the other compartments and it cannot correct a notable angulation. So choosing the right patient for a partial knee replacement is important. By far, the majority of partial replacements are for the medial or inner part of the knee. Sometimes they are considered in patients who are “too young” for a knee replacement with the hope that the partial replacement will give relief for some years and then can be converted to a total knee replacement.