Department of Orthopaedic Surgery, Okayama University, Okayama, Japan.
Department of Orthopaedic Surgery, Asahigawaso Children's Welfare and Medical Centre, Okayama, Japan.
Hip Int. 2022 Nov;32(6):800-806. doi: 10.1177/11207000211004917. Epub 2021 Apr 8.
Residual acetabular dysplasia of the hip after open reduction can complicate the treatment of developmental dysplasia of the hip (DDH) due to the potential need for corrective surgery. This retrospective study aimed to determine the predictive factors for acetabular development using postoperative radiographs and magnetic resonance imaging (MRI).
We retrospectively investigated 74 hips of patients with DDH who underwent open reduction after reaching walking age and were followed up radiologically until skeletal maturity. We evaluated the cartilaginous acetabulum and labrum using a new method that measures the cartilaginous and labral landmarks on coronal and axial MR T2*-weighted images in patients aged 5 years. The mean age at the time of surgery was 22 months and that at the final survey was 20 years. Severin classification was determined at the final follow-up. Groups with good (53 hips) and poor (21 hips) outcomes were compared using the postoperative radiographic and MRI parameters recorded at 5 years of age. Factors predicting acetabular development were identified using univariate and multiple logistic analyses.
There were no significant differences in the bony-acetabular index (AI) and centre-edge (CE) angle between the good and poor outcome groups. However, the poor outcome group had significantly larger cartilaginous- and labral-AIs but significantly smaller cartilaginous- and labral-CE angles than the good outcome group (both < 0.05). Multiple logistic regression analysis showed that labral-AI and labral-CE angle were predictors of acetabular development after open reduction for DDH, and their optimal cut-offs were 4° (77% sensitivity, 76% specificity) and 37° (68% sensitivity, 85% specificity), respectively.
Normal cartilaginous acetabulum development occurs in childhood, and evaluation using only radiographs is difficult. However, labral-AI ⩾4° and labral-CE angle <37° on MRI at 5 years of age offer useful indications for corrective surgery in patients with DDH.
髋关节切开复位后残余髋臼发育不良可能会使发育性髋关节发育不良（DDH）的治疗复杂化，因为可能需要进行矫形手术。本回顾性研究旨在通过术后 X 线和磁共振成像（MRI）确定髋臼发育的预测因素。
我们回顾性调查了 74 例在行走年龄后接受切开复位的 DDH 患者，这些患者接受了 X 线随访至骨骼成熟。我们使用一种新方法评估软骨髋臼和盂唇，该方法在冠状和轴向 MR T2*-加权图像上测量软骨和盂唇的标志，研究对象为 5 岁的患者。手术时的平均年龄为 22 个月，最终随访时的平均年龄为 20 岁。最终随访时采用 Severin 分类法。使用 5 岁时记录的术后 X 线和 MRI 参数比较结果良好（53 髋）和结果不良（21 髋）的两组。使用单变量和多变量逻辑分析确定预测髋臼发育的因素。
在骨髋臼指数（AI）和中心边缘（CE）角方面，结果良好组和结果不良组之间无显著差异。然而，结果不良组的软骨和盂唇 AI 显著增大，但软骨和盂唇 CE 角显著减小（均<0.05）。多变量逻辑回归分析显示，盂唇 AI 和盂唇 CE 角是 DDH 切开复位后髋臼发育的预测因素，其最佳截断值分别为 4°（77%的敏感性，76%的特异性）和 37°（68%的敏感性，85%的特异性）。
儿童期正常的软骨髋臼发育，仅通过 X 线评估较为困难。然而，5 岁时 MRI 上盂唇 AI ⩾4°和盂唇 CE 角<37°为 DDH 患者的矫形手术提供了有用的指征。
