Unicompartmental (partial or unicondylar) knee replacement is suitable for some patients where only part of the knee is affected by arthritis. The knee is made up of three compartments, medial, lateral and patelofemoral. In this unicompartmental knee replacement only the diseased compartment of the knee is replaced and the remainder of the knee is left untouched. The incision is smaller and, unlike total knee replacement, no ligaments have to be removed. Recovery from unicompartmental knee replacement is usually faster than for total knee replacement and knee function may also be better. Dr MacKenzie performs robotic assisted unicompartmental knee replacement at Lingard Hospital.