Risk Factors For Osteonecrosis Following Surgery For Treatment Of Developmental Dysplasia Of The Hip And The Impact Of Osteonecrosis On Acetabular Remodeling

Objective:to analyze risk factors for osteonecrosis(ON)following open reduction,pelvic osteotomy combined with proximal femoral osteotomy and the impact of osteonecrosis on subsequent acetabular development.Methods:Medical records of 79 patients(94 hips)with DDH who had undergone open reduction,Salter or Pemberton osteotomy combined with proximal femoral osteotomy from 2012 to 2015 with an average age of 33months(range,18~60 months)were collected retrospectively.Patients were divided into group A(18~35 months,64 hips)and group B(36~60 months,30 hips)based on age.ON was classified according to the criteria described by Bucholz-Ogden.Postoperative radiological outcomes were evaluated with use of the Severin criteria and measurement of acetabular index and center-edge angle.Results:All cases were followed up with average time of 34 months(range,14 ~ 62 months).9.6% of patients were classified as having Bucholz-Ogden type II to IV ON.Age,gender,laterality,preoperative traction,preoperative AI,Tonnis grading,surgery method,operation time,bleeding volume and follow-up time were not the risk factors of ON with use of logistic regression analysis.In the osteonecrosis-absent group,89.4% of patients showed a radiologically satisfactory result while only44.4% of patients in osteonecrosis group had a radiologically satisfactory result(P=0.003).There were significant differences between two groups with respect to last follow-up AI(P=0.033)and CEA(P=0.004).Conclusion:Age,gender,laterality,preoperative traction,preoperative AI,Tonnis grading,surgery method,operation time,bleeding volume and follow-up time are not the risk factors of ON.ON compromised postoperative acetabular development significantly.