Modified Dunn osteotomy using an anterior approach used to treat 26 cases of SCFE.

INTRODUCTION: Osteotomy performed below the femoral neck plays a leading role in the treatment of slipped capital femoral epiphysis (SCFE). It results in anatomical reduction. Several modifications have been made to Dunn's original osteotomy technique. We have developed another modification to this technique that uses an anterior surgical approach on a traction table with fluoroscopy control.

HYPOTHESES: Will this technique help to reduce the number of complications? Will its results be superior to those achieved with the standard Dunn osteotomy procedure?

MATERIAL AND METHODS: This was a retrospective single-center study of 26 cases in 24 patients (2 bilateral cases). Patients were positioned supine on a traction table with fluoroscopy control. An anterior surgical approach was used. A trapezoid-shaped osteotomy was performed below the femoral head. The head's reduction was checked on the fluoroscope and the fixation confirmed. The Postel Merle d'Aubigné (PMA) score was used for the clinical assessment. The radiographic assessment was based on Southwick's angle.

RESULTS: The mean slip angle of the femoral head was 57°. A mean correction of 47° was achieved. Based on the PMA score, good and excellent results were achieved in 20 cases (77%) and poor results occurred in 6 cases (23%). The surgical treatment had a significant effect on the PMA score (P=0.0008). In terms of complications, there were five cases of chondrolysis and one case of necrosis associated with chondrolysis.

DISCUSSION: The anterior approach provides direct access to the femoral neck, and thereby a cautious osteotomy at the site of the slip itself. Use of a traction table makes the external manipulations, reduction and fixation procedures easier to carry out. The results of this study were comparable to published results.

LEVEL OF PROOF: IV, retrospective treatment study.