With careful selection of cases and the proper operative approach, the authors feel that open operative correction by transcervical osteotomy and internal fixation gives the best chances for good function of the hip joint. In the slipped upper femoral epiphysis with malunion, because of the re-establishment of a normal anatomical relationship, the chance of this good function persisting into later life is excellent. Sixty-eight per cent. of the hips operated upon by this method had good hip-joint function, some having been observed as long as twelve years after the operation. We feel that this percentage justifies our continuance of this operative procedure.

Blind fixation of the epiphyseal line in the preslipped and early phases of slipping insures against the possibility of subsequent, more extensive, displacement. Such a procedure does not predispose the hip to the development of arthritis.

The two major complications arising as a result of the operations on the hip for this condition are traumatic arthritis and aseptic necrosis. Only 4 per cent. of the hips which were operated upon revealed roentgenographic evidence of aseptic necrosis; consequently it is not a frequent complication of the operation. Definite evidence of traumatic arthritis was present in 24 per cent. As this developed in two patients in whom no therapy had been attempted and in two in whom blind nailing had been performed, it has led the authors to conclude that the operative procedure is not the only factor contributing to this complication, but that some intrinsic predisposition toward this complication exists in this peculiar condition.