Outcome Comparison Between Closed And Open Reduction For Developmental Dysplasia Of The Hip In Children Aged 6-24 Months

Objective: To compare the early outcome between closed reduction(CR)and open reduction(OR)in 6-24 months children with developmental dysplasia of the hip(DDH),who can be reduced stably and safely by closed manipulation but with a widening joint space.Methods: From August 2012 to October 2017,77 patients(85 hips)with DDH were treated by CR or OR,and their medical data were reviewed retrospectively.51patients(56 hips)underwent CR,and 26 patients(29 hips)underwent OR.The demographic data,International Hip Dysplasia Institute(IHDI)grade and the Acetabular index(AI)before reduction were analyzed.At the last follow up,the Center-edge angle(CEA),AI,Alsberg Angle(AA),Reimer’s migration index(RMI),Height-to-width index of the epiphysis(HWI)were measured and compared between CR and OR group respectively.Meanwhile,the percentage of AVN,Residual acetabular dysplasia(RAD),HWI<0.357,RMI>33%,AA>81°,and coxa magna more than 15% of the normal side were calculated.Results: No significant statistical difference were found in sex,side,age at reduction,and follow time between CR and OR group;the dislocated severity between the two groups was similar when merging IHDI grade Ⅱ and Ⅲ(P=0.234);the AI before reduction was 37.30°±6.15° for CR group and 36.45°±6.06° for OR group respectively(P=0.543).There was no statistical difference in improvement of AI,CEA,HWI and RMI at the time of last follow up.The AA in CR group was77.66° ± 6.84°,and that was 81.97° ± 4.33° in OR group(P=0.001);accordingly,there were 32.14% and 58.62% hips with an AA>81° respectively(P=0.019).The frequency of coxa magna more than 15% of the normal side was higher in OR group(60.9%)than that in CR group(6.5%)(P<0.001);the percentage of RAD,HWI<0.357,RMI>33% and AVN were not statistically different.Conclusions: In children with DDH aged 6-24 months,if a stable and safe closed reduction can be obtained but with a widening joint space,an open reduction may not benefit acetabular remodeling more so than closed reduction.Therefore,closed reduction is recommended for those patients.