Aims The optimal bearing surface design for medial unicompartmental knee arthroplasty (UKA) remains controversial. The aim of this study was to compare outcomes of fixed-bearing (FB) and mobile-bearing (MB) UKAs from a single high-volume institution. Methods Prospectively collected data were reviewed for all primary cemented medial UKAs performed by seven surgeons from January 2006 to December 2022. A total of 2,999 UKAs were identified, including 2,315 FB and 684 MB cases. The primary outcome measure was implant survival. Secondary outcomes included 90-day and cumulative complications, reoperations, component revisions, conversion arthroplasties, range of motion, and patient-reported outcome measures. Overall mean age at surgery was 65.7 years (32.9 to 94.3), 53.1% (1,593/2,999) of UKAs were implanted in female patients, and demographics between groups were similar (p > 0.05). The mean follow-up for all UKAs was 3.7 years (0.0 to 15.6). Results Using revision for any reason as an endpoint, five-year survival for FB UKAs was 97.2% (95% CI 96.4 to 98.1) compared to 96.0% for MB (95% CI 94.1 to 97.9; p = 0.008). The FB group experienced fewer component revisions (14/2,315, 0.6% vs 12/684, 1.8%; p < 0.001) and conversion arthroplasties (38/2315, 1.6% vs 24/684, 3.5%; p < 0.001). A greater number of MB UKAs underwent revision due to osteoarthritis progression (FB = 21/2,315, 0.9% vs MB = 16/684, 2.3%; p = 0.003). In the MB group, 12 (1.8%) subjects experienced bearing dislocations which required revision surgery. There were 15 early periprosthetic tibia fractures (0.6%) in the FB group compared to 0 for MB (p = 0.035). Conclusion In similar patient populations, FB UKAs demonstrated slightly higher survival than a commonly used MB design. Adverse event profiles differed by bearing type, with an increased risk of bearing dislocation and OA progression with MB designs, and early periprosthetic tibia fractures for FB designs.

中文翻译：

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固定与移动轴承内侧单间室膝关节置换术的结果。


目的 内侧单间室膝关节置换术 (UKA) 的最佳支撑表面设计仍然存在争议。本研究的目的是比较单个高容量机构的固定轴承 (FB) 和移动轴承 (MB) UKA 的结果。方法 对 2006 年 1 月至 2022 年 12 月 7 名外科医生进行的所有初次骨水泥内侧 UKA 前瞻性收集的数据进行回顾。总共确定了 2,999 个 UKA，其中 2,315 例 FB 病例和 684 例 MB 病例。主要结果指标是种植体存活率。次要结局包括 90 天和累积并发症、再次手术、部件修正、关节置换术、活动范围和患者报告的结局指标。手术时的总体平均年龄为 65.7 岁（32.9 至 94.3），53.1% (1,593/2,999) 的 UKAs 植入女性患者中，各组之间的人口统计数据相似 (p > 0.05)。所有 UKA 的平均随访时间为 3.7 年（0.0 至 15.6）。结果 以任何原因的修正作为终点，FB UKA 的五年生存率为 97.2%（95% CI 96.4 至 98.1），而 MB 的五年生存率为 96.0%（95% CI 94.1 至 97.9；p = 0.008）。 FB 组的组件翻修次数较少（14/2,315，0.6% vs 12/684，1.8%；p < 0.001）和关节置换术（38/2315，1.6% vs 24/684，3.5%；p < 0.001） 。由于骨关节炎进展，更多的 MB UKA 接受了翻修（FB = 21/2,315，0.9% vs MB = 16/684，2.3%；p = 0.003）。在 MB 组中，12 名（1.8%）受试者出现轴承脱位，需要进行翻修手术。 FB 组有 15 例早期假体周围胫骨骨折 (0.6%)，而 MB 组为 0 例 (p = 0.035)。结论 在相似的患者群体中，FB UKA 的生存率略高于常用的 MB 设计。 不良事件概况因轴承类型而异，MB 设计的轴承脱位和 OA 进展的风险增加，FB 设计的早期假体周围胫骨骨折的风险增加。