Conflicting reports exist about the effect of offset variation on functional outcomes following total hip arthroplasty. Reproducing native hip offset is thought to optimize function by restoring biomechanics and appropriately tensioning the hip abductor muscles. The aim of this study is to assess the effect of failing to restore global hip offset in comparison to the native contralateral hip. A retrospective analysis of a prospective patient cohort was performed on patients undergoing an elective primary total hip arthroplasty. A total of 414 patients who had a minimum of 12 months of follow-up were included. Postoperative plain radiographs were analyzed for offset and compared to the contralateral native hip. Western Ontario and McMaster Universities Arthritis Index (WOMAC) and Veterans RAND 12 (VR-12) scores were assessed preoperatively and at 12 months postoperatively. Regression analyses indicated that a reduction in offset of >20 mm resulted in worse WOMAC pain ( = .005) and motion ( = .015) scores compared to those with maintained offset. WOMAC function ( = .063), global ( = .025), and VR-12 scores were not affected (physical = .656; mental = .815). Reduction in offset up to 20 mm and increased offset were not significantly associated with patient-reported outcome measures (-values ranged from .102 to .995). This study demonstrated an association between reduction in offset by >20 mm and worse WOMAC pain and motion scores following total hip arthroplasty. Surgeons should avoid decreases in offset >20 mm in order to optimize functional outcomes.

中文翻译：

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偏移的减少与全髋关节置换术后更差的功能结果相关

关于偏移变化对全髋关节置换术后功能结果的影响存在相互矛盾的报道。复制原生髋关节偏移被认为可以通过恢复生物力学和适当拉紧髋关节外展肌来优化功能。本研究的目的是评估与天然对侧髋关节相比，未能恢复整体髋关节偏移的影响。对接受选择性初次全髋关节置换术的患者进行前瞻性患者队列的回顾性分析。共有 414 名患者接受了至少 12 个月的随访。分析术后平片的偏移情况并与对侧原生髋关节进行比较。术前和术后 12 个月评估西安大略大学和麦克马斯特大学关节炎指数 (WOMAC) 和退伍军人 RAND 12 (VR-12) 评分。回归分析表明，与保持偏移量相比，偏移量减少 > 20 mm 会导致 WOMAC 疼痛 (= .005) 和运动 (= .015) 评分更差。 WOMAC 功能 ( = .063)、全局 ( = .025) 和 VR-12 评分未受影响（身体 = .656；心理 = .815）。偏移量减少最多 20 毫米和偏移量增加与患者报告的结果测量值没有显着相关性（值范围为 0.102 至 0.995）。这项研究表明，全髋关节置换术后偏移量减少 >20 mm 与 WOMAC 疼痛和运动评分恶化之间存在关联。外科医生应避免偏移量减少 >20 毫米，以优化功能结果。