Does Hip Stability Influence Rates of Acetabular Remodeling Following Reduction of Idiopathic Developmental Hip Dysplasia? A Comparison of Closed Versus Open Reduction With and Without Ligamentum Teres Reconstruction

BACKGROUND: The purpose of this study is to compare acetabular remodeling rates in age and severity matched, idiopathic DDH patients undergoing closed reduction (CR) versus open reduction alone (OR) versus open reduction supplemented by ligamentum teres reconstruction (LTR) utilizing a suture button device. METHODS: Prospectively obtained data of patients who underwent open reduction with LTR were compared with historic cohorts of children 2.5 years or younger who underwent CR or OR. Acetabular index (AI) was measured on radiographs taken prior to reduction and on serial postoperative follow-ups. Monthly and yearly rates of AI change were calculated. Subgroup analysis of the prospective LTR cohort was performed to characterize how the rate of acetabular remodeling changes with increasing time after surgery. RESULTS: Sixty-three patients with 71 hips underwent surgical reduction: 28 patients (29 hips) with CR, 19 patients (24 hips) with OR, and 16 patients (18 hips) with LTR. The average follow-up was 33.6 months. An annual acetabular index (AI) improvement of 7.9° was identified in the LTR cohort compared with 4.7° for OR and 4.0° for CR (P≤0.001). No patients within the LTR cohort have undergone subsequent pelvic osteotomy for residual dysplasia, versus 12.5% and 34.5% of the OR and CR groups, respectively. LTR patients demonstrated their greatest remodeling during the first year after surgery (1.0° per month). Rates decreased during the second year postoperatively (0.4° per month) and beyond (0.3° per month) (P=0.007). CONCLUSIONS: Short-term results suggest that enhanced stability provided by LTR may permit more robust acetabular remodeling and lead to less residual dysplasia in patients with idiopathic DDH. LEVEL OF EVIDENCE: Level II.