Fifty-two patients (sixty knees) who had a diagnosis of either patellar subluxation or dislocation had an operation consisting of a lateral release and proximal realignment of the patella. The duration of follow-up ranged from two to nine years. At the latest follow-up, forty-two (80.8 per cent) of the patients had a good or an excellent clinical result; only one patient had redislocation of the patella. The results were not affected by the grade of chondromalacia that was present at the time of operation; however, the differences in the results as correlated with the age and sex of the patient were statistically significant, the older patients having poorer results and the male patients, better results. Roentgenographic analysis of the postoperative position of the patella, as seen on the view described by Merchant et al., revealed that centralizing the patella in the intercondylar sulcus yielded the most favorable results.