We report a patient with nail patella syndrome associated with congenital permanent dislocation of the patella successfully operated on using a modified Stanisavljevic method. The patient, a 26-year-old woman, complained of inability to completely extend her right knee joint. She had occasionally experienced the "giving way" phenomenon since childhood, but she had not received any treatment since birth. Physical examination showed that all fingernails were deformed, with longitudinal striations, while the lunules were of an abnormal triangular shape or were missing. Both patellae were palpably hypoplastic, with the right patella dislocated laterally, and the knee had an extension lag of 90 degrees. Thigh and leg muscle were slightly underdeveloped, but quadriceps muscle contraction was good. Several radiographs were taken and they showed bilateral iliac horns and hypoplasia of the bilateral humero-radial joints and of both patellae, and complete dislocation of the right patella. We employed the Stanisavljevic procedure for the reduction of the patella, with Z-lengthening of the rectus femoris and medial translocation of the tibial tuberosity. Four years after the operation, a 30-degree extension lag still exists in the right knee, but the treatment resulted in stable alignment of the quadriceps mechanism, and notably improved gait appearance.