The modified Dunn procedure for slipped capital femoral epiphysis does not reduce the length of the femoral neck

OBJECTIVE: The treatment of slipped capital femoral epiphysis (SCFE) is evolving, with the development of new surgical techniques. |We wanted to study if modified Dunn procedure restores the normal alignment of the proximal femur and the risk of avascular necrosis is increased. METHODS: This is a single centre, retrospective study, comparing the outcomes of in situ pinning and modified Dunn procedure. Between 2001 and 2014, 7 children (7 hips) underwent the modified Dunn procedure and 10 children (10 hips) pinning in situ for stable and unstable SCFE. Mean age of the patients was 12.7 years with a median follow-up of 18 months. RESULTS: The radiological parameters improved in the modified Dunn procedure group, while the length of the femoral neck didn’t change significantly (p=0.09). Postoperative clinical outcomes were slightly better in the modified Dunn procedure group (6 hips out of 7 had good and excellent results) compared to the pinning in situ group (8 good and excellent results out of 10 hips) (p=0.04). No avascular necrosis was found and there were no cases of chondrolysis. CONCLUSION: Radiographic parameters of the proximal femur assessed in our study improved in all hips that underwent modified Dunn procedure, without the creation of secondary deformities.