Knee movements are usually recovered rapidly, particularly since we have used a small incision without dislocation of the patella. Early flexion need not be encouraged since it occurs spontaneously in most patients. Occasionally, however, manipulation under anaesthesia has been employed if the knee has not recovered 90° flexion at six weeks. In these cases, unlike manipulation of a stiff joint after TKA, there are no adhesions in the suprapatellar pouch that need to be ruptured and the knee flexes fully with the application of little force.
Extension improves spontaneously after OUKA and seldom lacks more than 2°–3° at the end of the first year. If a fixed flexion deformity persists, it is usually because osteophytes in the roof of the notch or on the tibia in front of the ACL insertion have not been removed at the time of surgery.