An analysis of the serial radiographs of sixty-eight patients who were treated for congenital dislocation of the hip revealed that a growth disturbance of the proximal end of the femur that was caused by partial or complete physeal closure developed in thirty-three of these patients. The disturbances were related to the character of the metaphyseal growth-disturbance lines and were subsequently classified according to the site and extent of physeal closure. In order to study this problem, we divided the physis of the proximal end of the femur into two contiguous sections: a medial and a lateral portion. Two typical patterns of premature closure were identified: one located at the junction of the medial and lateral portions of the physis and the other located in the area of the medial portion of the physis alone. The pattern of physeal closure, together with the age of the patient at the time of closure, determines the subsequent growth of the proximal end of the femur. The final outcome of growth of the proximal end of the femur can be predicted within six months after the initial treatment. Epiphyseal changes were found to be of no prognostic significance in the absence of physeal closure.