Department of Orthopedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
Int Orthop. 2019 Sep;43(9):2057-2063. doi: 10.1007/s00264-018-4154-x. Epub 2018 Sep 24.
To achieve sufficient socket coverage by the native bone, high placement of cementless acetabular cup is often required. We previously reported, using computer simulation, that higher hip centre improved the bone coverage but decreased the range of motion in total hip arthroplasty (THA) for patients with hip dysplasia. However, in a clinical setting, the correlation between the hip centre height and dislocation after primary THA is still unclear. We examined whether a high hip centre affects dislocation after THA.
A total of 910 patients, with 1079 dysplastic hips, who underwent primary THA were retrospectively reviewed. The age at THA averaged 63.0 years and mean follow-up was 74.3 months. Vertical centre of rotation (V-COR) was defined as the distance from the head centre to the interteardrop line. Uni- and multivariate logistic regression models were applied to identify significant factors affecting dislocation.
Ten hips in nine patients (0.9%) had dislocation after THA. In univariate analysis, age at surgery and V-COR were significant risk factors for dislocation. Multivariate analysis identified advanced age at operation (odds ratio [OR] 1.8/5 years), Crowe classification (OR 15.6), V-COR (OR 3.1/5 mm), and femoral head size (OR 11.6) as independent risk factors for dislocation. Receiver operating characteristic curve analysis revealed the cutoff value of the V-COR for dislocation as 23.9 mm.
A higher hip centre with the V-COR > 23.9 mm affected dislocation after THA for DDH. Our results would be useful for reconstruction of the hip centre, particularly with cementless acetabular cups.
为了使原生骨充分覆盖髋臼，常需要将非骨水泥髋臼杯高位放置。我们之前通过计算机模拟发现，对于髋关节发育不良的患者，较高的髋关节中心位置可改善骨覆盖，但会减小全髋关节置换术（THA）的活动范围。然而，在临床环境中，初次 THA 后髋关节中心位置与脱位之间的相关性尚不清楚。我们研究了高髋关节中心位置是否会影响 THA 后的脱位。
回顾性分析了 910 例（1079 髋）接受初次 THA 的髋关节发育不良患者。THA 时的平均年龄为 63.0 岁，平均随访时间为 74.3 个月。垂直旋转中心（V-COR）定义为股骨头中心到泪滴线的距离。采用单因素和多因素逻辑回归模型来确定影响脱位的显著因素。
9 例患者的 10 髋（0.9%）发生 THA 后脱位。单因素分析中，手术时的年龄和 V-COR 是脱位的显著危险因素。多因素分析确定了手术时年龄较大（优势比[OR]每 5 岁增加 1.8）、Crowe 分类（OR 15.6）、V-COR（OR 每增加 5mm 增加 3.1）和股骨头大小（OR 11.6）是脱位的独立危险因素。受试者工作特征曲线分析显示，V-COR 的脱位截断值为 23.9mm。
V-COR > 23.9mm 的较高髋关节中心位置会影响 DDH 患者 THA 后的脱位。我们的结果对于髋关节中心位置的重建，特别是非骨水泥髋臼杯的重建，将是有用的。
