Patellar compression syndrome may be a manifestation of contraction of the lateral retinacular structures which consists largely of the lateral patellofemoral ligament producing a tethering action on the patella. This may produce parapatellar pain, particularly in activities requiring repetitive knee flexion. Minor patellofemoral incongruencies with pain, grating, and functional limitation may be found on examination but the patient does not demonstrate the problems of instability of marked congenital abnormalities often seen with other patellar problems. Forty patients underwent a simple release of the lateral retinaculum to decompress the patella in the patellofemoral groove. Follow-up was obtained in 31 patients at an average of 18.3 months after surgery. Twenty-four knees which had severe preoperative pain were converted to 6 with no pain, 4 with mild pain, 11 with moderate pain and 3 whose pain remained unchanged after surgery. Twenty knees with moderate preoperative pain were changed to 4 with no pain, 11 with mild pain and 4 whose pain remained unchanged. Thirty-seven of the 45 knees had lessening of the pain after the operation and 10 patients returned to unrestricted atheletic activities.