Retrospective Analysis of the Clinical and Radiological Outcomes Following Modified Dunn Osteotomy in Patients with Stable, Moderate-to-severe Chronic Slipped Capital Femoral Epiphysis

Abstract

Objective The management of slipped capital femoral epiphysis (SCFE) has been completely transformed by modified Dunn osteotomy, a subcapital realignment osteotomy achieved through a safe surgical dislocation technique originally described by Ganz. The purpose of this study was to evaluate the clinical and radiological outcomes of patients with moderate to severe SCFE after modified Dunn osteotomy. Methods A total of 15 patients (16 hips, with one bilateral case; 12 males, 3 females) aged from 10.2 to 17-years-old (mean: 14.3) with stable, moderate to severe, chronic SCFE (moderate: = 6; severe = 10) underwent modified Dunn osteotomy as treatment. The hip joint range of motion (ROM), Harris (HHS), and Merle d'Aubigné (MdA) hip scores were used for clinical assessments. They were assessed radiographically using the Southwick and Alpha angles. Results At the most recent follow-up (mean 8.6 years; 3.1-14), the mean hip joint ROM, the mean HHS (preoperative: 69.20 ± 5.94; postoperative: 86 ± 7.37; p < 0.00001), and the mean MdA score (preoperative: 12.47 ± 1.13; postoperative: 14.27 ± 1.83; p < 0.00001) all showed statistically significant clinical improvements The radiological results demonstrated improvements in the mean Southwick angle (preoperative: 56.60 ± 12.89°; postoperative: 16.40 ± 4.69°; p < 0.00001) and Alpha angle (preoperative: 101.87 ± 12.88°; postoperative: 29.33 ± 7.29°; p < 0.00001). There were two significant postoperative complications identified: femoral head avascular necrosis (AVN) and deep infection. Conclusion According to the study's findings, the modified Dunn osteotomy is a safe, efficient treatment option for stable moderate-to-severe chronic SCFE with a manageable risk of complications.

Keywords: hip; osteonecrosis; osteotomy; slipped capital femoral epiphysis.