Patellofemoral instabilities may result from several predisposing factors including excessive femoral anteversion, patellar dysplasia, genu valgum, trochlear dysplasia and joint hyperlaxity. Chronic patellar dislocation, the most severe type of disease, is associated with the congenital and untreated traumatic dislocation or contracture of the quadriceps, while congenital patellar dislocation, which is often bilateral, is associated with failure of internal rotation of the myotome including the extensor mechanism. Concomitant abnormalities may be seen and the patient has no complaint of pain until arthritis develops. Acute patellar dislocation is traumatic and lateral patellar dislocation or abnormal shifting during turning is present in the history of the patient. Unless treated appropriately, recurrent patellar dislocation which is characterized by may be seen catching sensation, locking and effusions, leading to osteochondral fractures. Finally, chronic patellar subluxation (incomplete dislocation), similar to excessive lateral compression syndrome, is another patellar instability, characterized by subtle sign of burning pain on superomedial portal of both knees. Treatment of patellar instabilities includes a wide range of modalities from using knee breeches to exercise programs and also from osteotomy to joint reconstruction.