[Study on the impact of labro-chondral complex on development of the acetabulum after close reduction in developmental dysplasia of the hip].

Objective: To explore the influence of the labro-chondral complex (LLC) on the development of the acetabulum after close reduction in developmental dysplasia of the hip (DDH). Methods: Sixty-one cases (72 hips) with DDH presented in Beijing Jishuitan Hospital were reviewed, all the patients were treated by closed reduction, arthrogram and Spica casting from March 2010 to December 2013. The anterior-posterior pelvic radiography was performed to evaluate the morphology of the labro-chondral complex and reduction of the hip. The cases were divided into Ⅰ, Ⅱ, Ⅲ, Ⅳ four groups according to the shape of the LLC initially, and when performed the secondary Spica cast after 3 months, these cases were divided into 0-0.4, 0.4-0.6, and >0.6, three groups based on the height difference ratio (HDR) of the LLC. The relationship between the shape and HDR of the LLC was analyzed. The AI and CE angle were used to evaluate development of the hip during the latest follow up. The impact of the shape and HDR of the LLC on the development of the acetabulum was explored as well. Results: The HDR was the least in the type Ⅰ hips, all cases were less than 0.6, the AI in this group was significantly lower than the others(24.33°±3.12°), and the CE angle was significantly higher in the type Ⅰ hips(15.22°±3.11°) during the latest follow up. The CE angle was significantly different among the three groups of HDR. The HDR was lower, the CE angle was higher. The AI in 0-0.4 group was significantly lower than the others(14.24°±3.10°). Conclusion: The shape of the LLC is helpful to judge development of the acetabulum when closed reduction was performed in DDH. And the HDR in the secondary cast change could be used as a sensitive index to predict development of the hip.