Isolated lateral retinacular release was performed on 102 knees in 76 patients. Diagnoses included chondromalacia patellae, patellar compression syndrome, and subluxation and dislocation of the patella. Patients reported that their symptoms improved after isolated lateral retinacular release in 95 of 102 knees. At follow-up evaluation (mean, 14.5 months after surgery), independent observers found no recurrence of dislocation in the 23 knees having had frank dislocations before surgery. In 71% of the knees with limitation of activity before surgery, unlimited activity was tolerated after isolated lateral retinacular release. Quadriceps exercise tolerance improved from 51% before surgery to 100% after surgery. This improvement in exercise tolerance can provide a significant length of time in which quadriceps rehabilitation can be conducted. Hypothetically, the effect of that lateral retinacular release is a decrease in the work load of an overpowered or weakened vastus medialis obliquus muscle, the major provider of dynamic stability required by the patellofemoral joint.