Contrary to prevailing opinion, supracondylar fractures can produce serious growth disturbances if the fracture lines extend into the epiphyseal centers. Cubitus varus and cubitus valgus are not considered serious disabilities, if flexion and extension are complete. However, if the deformity is progressive and is caused by disturbances in the growth centers, disabilities and limitation of motion may occur years after the initial injury.

A satisfactory reduction is one in which the alignment in both planes is good. An anterior or posterior displacement of the fragments, in which the articular surfaces are displaced to a corresponding degree, will produce permanent limitations of flexion and extension. Lateral displacement above the epiphyses will produce valgus and varus deformities, but a good functional elbow may still result.

Supracondylar fractures in which the fracture line, or part of it, extends into the epiphyses may produce growth disturbances similar to those which result from fractures of the lateral and medial condyles. If the fragment is intra-articular and not attached to overlying bone and soft tissue, it will undergo avascular necrosis. Supracondylar fractures of this type should have an accurate anatomical reduction; and, if the fragments are displaced and rotated, an open reduction is probably the best method of obtaining accurate alignment.

A series of lateral condylar fractures, in which there were poor results in 50 per cent, of the cases treated by closed reduction, speaks for the ineffectiveness of this method. Early open reduction with minimal trauma to soft tissues will give the best results. Avascular necrosis of the capitellum will occur if the fracture line separates the epiphysis from the overlying bone and soft tissues. Fractures of half of the capitellum occurred in two patients with lateral condylar fractures. One had poor apposition by open reduction, and avascular necrosis occurred in one year. In the other, the separation was not complete, the position was good, and healing was uneventful.

Avascular necrosis of the trochlea may occur later, despite a good reduction of a supracondylar fracture. It can cause stiffness at the joint, due to thinning of the cartilage and distortion of the articular surface of the humerus.

Delayed ulnar palsy may cause progressive growth disturbances, and was present in two cases of severe cubitus valgus deformity.

Fracture of the medial epicondyle will not cause a serious disability unless the fragment enters the joint cavity. Non-union is difficult to avoid in closed reduction.