Predictors for avascular necrosis of the femoral head in closed reduction following traction for developmental dysplasia of the hip

Avascular necrosis (AVN) is a serious complication associated with the treatment of developmental dysplasia of the hip (DDH). In this study, we analyzed 241 affected hips from 232 patients who underwent closed reduction following traction (CR/TR) between 1995 and 2021 to identify risk factors for AVN and establish clinical strategies to reduce its incidence. All patients received four weeks of traction (horizontal, vertical, and gradual abduction) followed by closed reduction. The severity of dislocation was assessed using the International Hip Dysplasia Institute (IHDI) classification and Yamamuro's distance a (YDA), with lower YDA values indicating more severe dislocation. AVN was evaluated on radiographs taken one to two years after reduction using Salter's criteria. Patients were divided into AVN( +) and AVN( -) groups for demographic and radiographic comparisons. AVN developed in 15% of hips. Logistic regression analysis identified two significant risk factors: left-sided involvement (odds ratio 3.15) and insufficient horizontal traction (YDA < 8 mm during traction). Among left-sided hips, a YDA < 8 mm was associated with a 32% incidence of AVN. Achieving a YDA of ≥ 8 mm during traction is essential to reduce the risk of AVN, especially in left-sided hips. These findings underscore the importance of evidence-based traction protocols to minimize AVN risk and improve outcomes in children with DDH.