Service de chirurgie orthopédique et réparatrice de l'appareil moteur du CHU de Rennes, hôpital Pontchaillou, 2, rue Henri-le-Guilloux, 35000 Rennes, France.
Service de chirurgie orthopédique et réparatrice de l'appareil moteur du CHU de Rennes, hôpital Pontchaillou, 2, rue Henri-le-Guilloux, 35000 Rennes, France.
Orthop Traumatol Surg Res. 2019 Nov;105(7):1303-1309. doi: 10.1016/j.otsr.2019.01.020. Epub 2019 May 29.
Reports of high dislocation rates after revision total hip arthroplasty (THA) have encouraged the widespread use of dual-mobility cups. Dislocation has been less common but not fully abolished with dual-mobility cups, and its causes have remained unidentified. The objectives of this retrospective matched case-control study were: 1) to identify risk factors for dislocation, 2) and to assess dislocation outcomes.
The causes of dislocation after revision THA with a dual-mobility cup can be identified.
Among 653 consecutive patients identified retrospectively as having undergone revision THA with a dual-mobility cup (Medial Cup, Aston, Saint-Étienne, France) between January 2007 and December 2017, 16 (2.45%) subsequently experienced dislocation, after a mean of 3.6 months (range, 0.9-19 months). For each of these 16 patients, we collected the main patient characteristics (age, sex, body mass index [BMI], ASA score, and reason for the initial arthroplasty procedure), local history (number of previous surgical procedures, reason for revision, femoral and acetabular bony defects classified according to Paprosky, and status of the abductor apparatus), and characteristics of the revision (approach, diameters of the cup and femoral head, cup inclination, femoral offset, lower limb length, and implant anteversion). Controls were patients without dislocation after revision dual-mobility THA. Each of the 16 patients was matched to 3 controls on age (±10 years), sex, year of revision, and whether revision was only acetabular or bipolar. Univariate and multivariate analyses were done to compare the cases and controls, and dislocation outcomes in the cases were evaluated.
By univariate analyses, factors associated with dislocation were BMI>30 (cases, 37.5%; controls, 10.4%; p=0.02), larger number of previous surgical procedures on the same hip (cases, 2.8; controls, 1.8; p=0.004), larger number of arthroplasties (cases, 2.3; controls, 1.5; p=0.004), history of instability (cases, 31% with chronic dislocation and 13% with recurrent dislocation; controls, 6.25% and 2.1%, respectively; p=0.004), and compromised abductor apparatus (cases, 56.25%; controls, 14.6%; p=0.002). Independent risk factors for dislocation identified by multivariate analysis were instability (odds ratio [OR], 14.5; 95% confidence interval [95%CI], 1.5-149.9) and, most importantly, abductor apparatus compromise (OR, 43.1; 95%CI, 3.18-586.3). Of the 16 cases, 1 was lost to follow-up, 1 had contra-indications to anaesthesia, 1 died after several dislocation episodes, and 1 died 3 months after surgical reduction. In 5 cases, there was a single dislocation episode. Further surgery was performed in 8 cases (surgical reduction, n=1; constrained cup, n=3; trochanteric internal fixation, n=1; exchange of the dual-mobility cup, n=2, including 1 with subsequent dislocation episodes; and femoral component exchange followed by a retentive cup due to further dislocation episodes, n=1).
Risk factors for dislocation consisted of a history of instability and, most importantly, abductor apparatus compromise. A constrained cup should be considererd in patients with impaired abductor apparatus. No further dislocations occurred after reduction of the first episode in 31.25% of cases. Recurrent dislocation should prompt measures to correct impaired abductor apparatus whenever possible, as well as correction of any component malposition. Whether a retentive cup should be implanted routinely remains unclear.
III, matched case-control study.
翻修全髋关节置换术后（THA）高脱位率的报道促使广泛使用双动杯。 使用双动杯后脱位虽较少见，但并未完全消除，其原因仍未确定。本回顾性匹配病例对照研究的目的是：1）确定脱位的危险因素，2）评估脱位的结果。
可以确定双动杯翻修 THA 后脱位的原因。
回顾性确定 2007 年 1 月至 2017 年 12 月期间接受 Medial Cup（Aston，Saint-Étienne，法国）双动杯翻修的 653 例连续患者中，16 例（2.45%）在平均 3.6 个月（0.9-19 个月）后发生脱位。对于这 16 名患者中的每一位，我们收集了主要的患者特征（年龄、性别、体重指数[BMI]、ASA 评分和初次关节置换手术的原因）、局部病史（手术次数、翻修原因、根据 Paprosky 分类的股骨和髋臼骨缺损以及外展肌装置的状态）和翻修特征（入路、杯和股骨头直径、杯倾斜度、股骨偏心距、下肢长度和植入物前倾角）。对照组为无双动杯翻修 THA 后脱位的患者。16 名患者中的每一位都与年龄（±10 岁）、性别、翻修年份和翻修是仅髋臼还是双极相匹配的 3 名对照。进行了单变量和多变量分析以比较病例和对照组，并评估了病例的脱位结果。
通过单变量分析，与脱位相关的因素包括 BMI>30（病例，37.5%；对照组，10.4%；p=0.02）、同一髋关节上手术次数较多（病例，2.8；对照组，1.8；p=0.004）、假体数量较多（病例，2.3；对照组，1.5；p=0.004）、不稳定病史（病例，31%有慢性脱位和 13%有复发性脱位；对照组，分别为 6.25%和 2.1%；p=0.004）和外展肌装置受损（病例，56.25%；对照组，14.6%；p=0.002）。多变量分析确定的脱位独立危险因素为不稳定（比值比[OR]，14.5；95%置信区间[95%CI]，1.5-149.9）和最重要的外展肌装置受损（OR，43.1；95%CI，3.18-586.3）。在 16 例病例中，1 例失访，1 例麻醉禁忌，1 例在多次脱位后死亡，1 例在手术后 3 个月死亡。在 5 例中，仅发生了一次脱位。8 例患者进一步手术（手术复位，n=1；约束杯，n=3；转子内固定，n=1；双动杯更换，n=2，包括 1 例随后发生脱位）和 1 例由于进一步脱位，更换了股骨组件和保留杯）。
脱位的危险因素包括不稳定病史和最重要的外展肌装置受损。对于外展肌装置受损的患者，应考虑使用约束杯。在 31.25%的病例中，首次复位后未再发生脱位。只要有可能，应采取措施纠正受损的外展肌装置，以纠正任何组件位置不当，以防止复发性脱位。是否应常规植入保留杯仍不清楚。
III，匹配病例对照研究。
