Protective effect of modified lange "second position" for developing avascular necrosis following closed reduction for developmental dysplasia of the hip

BackgroundDevelopmental Dysplasia of the Hip (DDH) is a condition affecting hip joint development in children, presenting multiple manifestations. Immobilization methods to ensure hip concentricity, such as the human position and modified Lange position, vary in effectiveness and risks, especially avascular necrosis. The purpose of this study was to identify whether closed reduction (CR), with two different immobilization techniques, is effective in avoiding complications such as residual hip dysplasia (RHD), re-dislocation, and Avascular Necrosis (AVN).MethodsA total of 66 patients with DDH (84 hips) were treated with two different techniques of immobilization (groups A and B); the mean age at the time of reduction was 8 (6-13) months. The rates of RHD, Re-dislocation, and AVN were determined with a minimum follow-up of 48 months in both techniques.ResultsThe Chi-square analysis conducted across the study groups unveiled that patients in Group B demonstrated a protective effect against AVN compared to those in Group A (OR: 0.248, 95% CI: 0.072-0.847, p = 0.026). However, no statistically significant differences were found between the groups concerning RHD (p = 0.563) and re-dislocation (p = 0.909).ConclusionsAfter the initial Human Position immobilization, the second cast with the modified Lange "second position" demonstrated a protective effect compared with maintaining the Human Position immobilization throughout the immobilization period, reducing the likelihood of AVN development in patients undergoing closed reduction for developmental dysplasia of the hip.