Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota.
J Arthroplasty. 2018 May;33(5):1501-1506. doi: 10.1016/j.arth.2017.11.055. Epub 2017 Dec 6.
Recurrent instability remains a challenge after revision total hip arthroplasty (THA). We report the outcomes of cementing a cementless dual mobility (DM) component into a stable acetabular shell for the treatment and/or prevention of instability in revision THA.
Eighteen patients (18 THAs) undergoing revision THA with a specific monoblock DM construct cemented into a new acetabular component or an existing well-fixed component from 2011 to 2014 were retrospectively reviewed. Tumor prostheses and total femoral replacements were excluded. In 9 patients (50%), components were implanted specifically for recurrent dislocations. Mean age was 64 years; mean follow-up was 3 years. Patients underwent an average of 4 prior hip operations (range 2-6).
No cemented DM cups dissociated at the cement-cup interface. Three patients (17%) experienced a postoperative dislocation. One required a revision to constrained liner and 2 underwent open reduction with retention of the DM construct. Harris Hip Scores improved from 53 to 82 postoperatively (P < .001).
Cementation of a monoblock cup DM construct, an off-label use as the construct is not specifically made for cementation, into a well-fixed acetabular component provides an alternative to enhance prosthetic stability in (1) recurrently dislocating THAs with well fixed, well-positioned acetabular components and (2) complex acetabular reconstructions in which constraint should be avoided. While not a perfect solution in this series, DM constructs provide a number of advantages including no added constraint at the interface and a large effective femoral head to diminish prosthetic impingement.
翻修全髋关节置换术（THA）后反复不稳定仍然是一个挑战。我们报告了将非骨水泥双动（DM）组件固定在稳定髋臼壳中的结果，用于治疗和/或预防翻修 THA 中的不稳定。
回顾性分析了 2011 年至 2014 年间接受特定单块 DM 结构翻修 THA 的 18 例患者（18 例髋关节）。排除了肿瘤假体和全股骨置换。在 9 例患者（50%）中，为了反复脱位，植入了特定的组件。平均年龄为 64 岁；平均随访 3 年。患者平均接受了 4 次髋关节手术（范围 2-6 次）。
没有固定 DM 杯在水泥杯界面处分离。3 例患者（17%）发生术后脱位。1 例需要更换约束衬垫，2 例需要开放复位并保留 DM 结构。术后 Harris 髋关节评分从 53 分提高到 82 分（P <.001）。
将单块杯 DM 结构（该结构并非专门用于固定）固定到固定良好的髋臼组件中是增强假体稳定性的一种替代方法，适用于（1）髋臼组件固定良好、位置良好但反复脱位的 THA，以及（2）需要避免约束的复杂髋臼重建。虽然在本系列中不是完美的解决方案，但 DM 结构提供了许多优点，包括在界面处没有增加约束和大的有效股骨头以减少假体撞击。
