Retrospective Comparison of Outcomes between Closed and Open Reduction for Developmental Dysplasia of the Hip in Children Aged 6–24 Months

Background: This study aimed to compare the early outcomes between closed reduction (CR) and open reduction (OR) in children aged 6–24 months with developmental dysplasia of the hip (DDH) who could be reduced safely and stably by the closed method. Methods: : We retrospectively reviewed the medical records of 77 patients who underwent CR or OR treatment for DDH from August 2012 to October 2017. Fifty-one patients (56 hips) underwent CR, while 26 (29 hips) underwent OR. The demographic data, International Hip Dysplasia Institute classification, and acetabular index (AI) before reduction were analysed. The centre-edge angle (CEA), AI, Alsberg angle (AA), Reimer’s migration index (RMI), and height-to-width index (HWI) of the epiphysis were compared between the CR and OR groups at the final follow-up. The percentages of avascular necrosis (AVN), residual acetabular dysplasia (RAD), HWI 33%, AA > 81˚, and coxa magna > 15% of the normal side were calculated. Results: : At the final follow up, the mean AA in the CR and OR groups were 77.66˚ (60˚–89˚) and 81.97˚ (73˚–91˚) ( p =0.001), respectively, and there were 32.14% and 58.62% of the hips with an AA > 81˚ ( p =0.019). The frequency of coxa magna > 15% of the normal side was higher in the OR group (60.9%) than in the CR group (6.5%) ( p <0.001). There was no difference in the improvement of AI, CEA, HWI, and RMI at the final follow-up. The percentages of RAD, HWI 33%, and AVN were not statistically different. Conclusion: In children aged 6–24 months with DDH, if a stable and safe CR can be obtained but with a widening joint space, an OR may not benefit acetabular remodelling more than a CR procedure, and thus, CR should be attempted.