1. It is suggested that abruptness of the condylar ridges on the femur plays a major role in the etiology of chondromalacia patellae. The medial condylar ridge is always abrupt in these cases, and indeed in many knees with no evidence of chondromalacia patellae. The lateral condylar ridge is rarely abrupt.

2. The short-term results of forty operations for reduction of femoral ridges in thirty-eight patients, with preservation of the patella in thirty-two cases, are satisfactory.