The Modified Dunn Procedure for Unstable Slipped Capital Femoral Epiphysis: A Systematic review and Meta-analysis

Abstract

Abstract Source of Support None, Conflict of Interest None. Background The management of unstable slipped capital femoral epiphysis is controversial and evolving as insight into the condition develops. Almost half of patients with unstable slip developed femoral head osteonecrosis. The modified Dunn procedure through safe surgical hip dislocation has rapidly gained popularity as a treatment for unstable slipped capital femoral epiphysis. In this review we analyzed the results and complications following this procedure. Materials and Methods We performed a retrospective chart review of 297 consecutive patients (302 hips) who had undergone the modified Dunn procedure through safe surgical hip dislocation from Feb 2009 to Feb 2017. Patients were169 males and 128 females, between the age group of 7 to 18 years (mean age 12.66 years) and BMI ranged from 14.7 to 42.1 Kg/m2 (mean BMI 26.32 Kg/m2). The duration of symptoms among the studied group ranged from 2 to 360 days with mean 84.75days. Regarding site and severity 57% had lesions in left side, 40.9% had lesions in right side, 2.1% had bilateral lesions and 58% had severe lesions. The duration of operation among the studied group ranged from 75 to 162 min with mean 128.19 min. Regarding time of operation 61.1% had operation after more than 24 h from admission. All the patients were assessed with slip angle degree, Harris hip score, alpha angle, flexion degree, internal rotation, external rotation and neck shaft angle. Results At the mean follow up of 26.3 months (range 12 months to 4.5 years), the mean slip angle improved from a preoperative Value10 to 80 degree with mean 55.6 degree and after operation it ranged from 0 to 28 degree with mean 6.7 degree with mean reduction 48.9 degree, the Harris hip score among the studied group after operation ranged from 46 to 100% with mean 90.98%, regarding post-operative range of motion alpha angle ranged from 23.6 to 52.8 degree with mean 44.3 degree, flexion ranged from 80 to 120 degree with mean 105.84 degree, internal rotation ranged from 5 to 60 degree with mean 30.08 degree and external rotation ranged from 10 to 60 degree with mean 42.3 degree and finally neck shaft angle ranged from 128 to 164 degree with mean 137.2 degree. Conclusion Unstable slipped capital femoral epiphysis is associated with a high rate of avascular necrosis. Etiology of the AVN is not completely known and likely multifactorial. The modified Dunn osteotomy through Ganz surgical hip dislocation is the treatment of choice for those with moderate and severe unstable SCFE, allowing anatomical restoration of proximal femur, direct inspection, and preservation of physeal blood supply and inspection of intra-articular pathology which can be evaluated and treated at the time of operation.