The results of arthroscopic lateral release of the extensor mechanism for recurrent dislocation of the patella after 8 years.

We reviewed 41 knees at a mean of 4 years after arthroscopic lateral release of the extensor mechanism. The operations were performed for recurrent complete dislocation, not for subluxation, maltracking, or lateral pressure syndrome. Thirty-three of these knees were reviewed again 8 years after operation. There were 39% excellent results according to the criteria of Crosby and Insall at 4 years and 30% at 8 years. Patellar stability improved between 4 and 8 years (p < 0.01). The results in patients with subluxation of the patella on extension of the knee or generalized ligament laxity were poor; five of seven patients with these conditions were worse and had undergone another operation. With these conditions excluded, the excellent results decreased from 50% after 4 years to 37% after 8 years. The results of lateral release are better than those reported after other procedures. It is concluded that arthroscopic lateral release is the procedure of choice for patients with recurrent complete dislocation of the patella unless there is abnormal ligament laxity or subluxation on extension. The operation should not be performed in the presence of these conditions.