Proximal and distal reconstruction of the extensor mechanism for patellar subluxation.

Proximal and distal reconstruction of the leg extensor mechanisms has been developed and performed in 346 cases over a period of 25 years. Proximal extensor mechanism reconstruction produces very satisfactory results in over 70% of cases and continues to be the basic principle of surgical treatment for patellar subluxation. In patients with Q angles (angle between line of the quadriceps force and the direction of the patellar tendon) greater than 10 degrees distal reconstruction (patellar tendon transfer) is done in addition to, not in lieu of, the dynamic proximal reconstruction. Treatment of the chondromalacia developing secondary to altered extensor mechanism mechanics can be by simple chondrectomy provided that the causal mechanical abnormalities are modified.