Aims:

Dislocation is a major cause of early failure after THA and is highly influenced by surgical approach and component positioning. Robotic-arm assisted arthroplasty has been developed in an attempt to improve component positioning and reduce postoperative complications.

The purpose of this study was to compare the rate of dislocation after robotic total hip arthroplasty through 3 different surgical approaches.

Materials and methods:

All patients who had undergone robotic arm-assisted THA at 3 centres between 2014 and 2019 were reviewed. After applying exclusion criteria, 1059 patients were included in the study. An anterior approach was used in 323 patients, a lateral approach in 394 and a posterior approach in 342 patients.

Episodes of dislocation were recorded after 6 months follow-up. Stem anteversion, cup anteversion, cup inclination and combined anteversion were collected using the integrated navigation system.

Cumulative incidence (CI), incidence rate (IR) and risk ratio (RR) were calculated with a confidence interval of 95%.

Results:

3 cases of dislocation (2 posterior approach, 1 anterior approach) were recorded, with a dislocation rate of 0.28% and an IR of 0.14%.

The rate of placement of the cup in the Lewinnek safe zone was 82.2% for the posterior approach, 82.0% for the lateral approach and 95.4% for the anterior approach.

The rate of placement in the combined version safe zone was 98.0% for the posterior approach, 73.0% for the lateral approach and 47.1% for the anterior approach.

The incidence rate of dislocation was 0.30% for the anterior approach, 0.34% for the posterior approach and 0% for the lateral approach.

Conclusions:

The robotic arm-assisted technique is associated with a low risk of dislocation. The combined version technique appears to be a reliable way to reduce the risk of dislocation through the posterolateral approach but does not appear to be essential when using the lateral and anterior approaches.

中文翻译：

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机械臂辅助全髋关节置换术后脱位风险：前、外侧和后外侧入路的比较

目标：

脱位是 THA 后早期失败的主要原因，并且受手术方法和组件定位的影响很大。已经开发了机械臂辅助关节成形术，以试图改善部件定位并减少术后并发症。

本研究的目的是通过 3 种不同的手术方法比较机器人全髋关节置换术后的脱位率。

材料和方法：

回顾了 2014 年至 2019 年间在 3 个中心接受过机械臂辅助 THA 的所有患者。应用排除标准后，1059 名患者被纳入研究。323 名患者使用了前路入路，394 名患者使用了外侧入路，342 名患者使用了后路入路。

随访 6 个月后记录脱位事件。使用集成导航系统收集茎前倾、杯前倾、杯倾和组合前倾。

以95%的置信区间计算累积发病率（CI）、发病率（IR）和风险比（RR）。

结果：

共记录3例脱位（后入路2例，前入路1例），脱位率为0.28%，IR为0.14%。

在 Lewinnek 安全区内，后路入路的杯子放置率为 82.2%，外侧入路为 82.0%，前路入路为 95.4%。

后入路在联合版本安全区的放置率为 98.0%，外侧入路为 73.0%，前路入路为 47.1%。

前入路的脱位发生率为0.30%，后入路为0.34%，外侧入路为0%。

结论：

机械臂辅助技术与低脱位风险相关。联合版本技术似乎是通过后外侧入路降低脱位风险的可靠方法，但在使用外侧入路和前入路时似乎不是必需的。