Lateral retinaculum release in adolescent patellofemoral disorders: its relationship to peripheral nerve injury in the lateral retinaculum.

Adolescent patellofemoral disorders which are associated with recognizable change in the articular cartilage of the patella are called chondromalacia patellae. This is a clinical syndrome characterized by persistent retropatellar pain, but not always associated with histopathological changes of the articular cartilage. When lateral retinacular release is performed in such patients, pain is frequently eased even though lateral release does not always cause an appreciable change in patellofemoral contact pressure. This suggests that pain, at times, may emanate from the peripatellar retinacular supports themselves. Thirty-five knees of 22 patients suffering from anterior knee pain (with or without an unstable patella) were investigated histologically. Pathological changes in nerves were graded on a 0 to 3 + scale of severity. There was severe degenerative neuropathy in nine knees, moderate change in nine, and slight change in 11; the remaining six knees were normal. Histological investigation of the resected lateral retinaculum suggested that pain originated in the lateral retinaculum in many patients, and that degenerative changes in the nerves of the lateral retinaculum may be an important cause of pain in patients with patellofemoral disorders.