Early open reduction of dislocated hips using a modified Smith-Petersen approach in arthrogyposis multiplex congenita

BACKGROUND: Arthrogryposis multiplex congenita (AMC) is a rare syndrome with multiple joint contractures. Within the medical community, there is controversy surrounding AMC in terms of the ideal surgical approach and age for performing a reduction of dislocated hips. The purpose of this retrospective study was to evaluate the clinical outcomes of early open reduction of infant hip dislocation with arthrogryposis multiplex congenita following a modified Smith-Petersen approach that preserves the rectus femoris. METHODS: From 2010 to 2017, we performed this procedure on 28 dislocated hips in 20 infants under 12 months of age with AMC. The clinical and radiology data were reviewed retrospectively. The mean age at surgery was 6.9 ± 5.1 months, with a mean follow-up of 42.4 ± 41.1 months. RESULTS: After open reduction, the average hip acetabular index (AI), the international hip dysplasia institute classification (IHDI), and the hip range of motion significantly improved (all P < 0.001). After the surgery, 16 patients were community walkers, and four patients were home walkers. Three hips in two patients required secondary revision surgery for residual acetabular dysplasia with combined pelvic osteotomy and femoral osteotomy. Seven of the hips that had been operated on showed signs of avascular necrosis (AVN). Among them, four were degree II, two were degree III, and one was degree IV. Multiple linear regression analysis demonstrated that greater age (in months) heightened the risk for secondary revision surgery (P = 0.032). CONCLUSIONS: The modified Smith-Petersen approach preserving the rectus femoris is an encouraging and safe option for treating hip dislocation in young AMC patients (before 12 months). If surgery takes place at less than 12 months of age for patients with AMC, this earlier open reduction for hip dislocation may reduce the chances of secondary revision surgery. LEVEL OF EVIDENCE: IV, retrospective non-randomized study.