Introduction

Recurrent dislocations are still the most frequent reason for revision in total hip arthroplasty (THA). The impact of bearing surfaces on dislocations is still controversial. We hypothesized that: (1) bearing surfaces influence the revisions due to dislocations; (2) ceramic-on-ceramic reduced the revisions for dislocations in adjusted models; (3) Delta-on-Delta bearings reduced the revisions for dislocations in comparison to surfaces with cross-linked polyethylene.

Materials and methods

The regional arthroplasty registry was enquired about bearing surfaces and revisions for dislocations and instability. Unadjusted and adjusted rates were provided, including sex, age (<65 years or ≥65 years), head diameter (≤28 mm or >28 mm; <36 mm or ≥36 mm) as variables. 44,065 THAs were included.

Results

The rate of revisions for dislocations was significantly lower in ceramic-on-ceramic and metal-on-metal bearings (unadjusted rates). After adjusting for age, sex, and head size (36 and 28 mm), hard-on-hard bearings were protective (p < 0.05): ceramic-on-ceramic had a lower risk of revisions due to dislocation than ceramic-on-polyethylene (HR 1.6, 95% CI 1.2–2.2 p = 0.0009). The rate of revisions for dislocation was similar in bearings with cross-linked polyethylene and Delta-on-Delta articulations, in unadjusted and adjusted models.

Conclusion

Bearings with conventional polyethylene were more predisposed to dislocations. Currently adopted bearings exerted no significant influence on revisions due to dislocations. These findings could be primarily related to wear, but due to the time distribution, soft tissue envelopes and surface tension may also play a role. Pre-clinical biomechanical evaluations and prospective matched cohort studies are required to draw definitive conclusions.

中文翻译：

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全髋关节置换术中承重面对脱位翻修的影响

介绍

复发性脱位仍然是全髋关节置换术 (THA) 翻修的最常见原因。轴承表面对位错的影响仍然存在争议。我们假设：（1）轴承表面由于错位而影响修正；(2) 陶瓷对陶瓷减少了调整模型中对位错的修正；(3) 与交联聚乙烯表面相比，Delta-on-Delta 轴承减少了对位错的修正。

材料和方法

向区域关节成形术登记处询问了轴承表面以及脱位和不稳定的翻修情况。提供了未调整和调整后的比率，包括性别、年龄（<65 岁或 ≥65 岁）、头部直径（≤28 mm 或 >28 mm；<36 mm 或 ≥36 mm）作为变量。包括 44,065 个 THA。

结果

陶瓷对陶瓷和金属对金属轴承的脱位修复率显着降低（未调整率）。在调整了年龄、性别和头部尺寸（36 和 28 毫米）后，硬对硬轴承具有保护性（p  < 0.05）：陶瓷对陶瓷因脱位而导致翻修的风险低于陶瓷对陶瓷。聚乙烯（HR 1.6, 95% CI 1.2–2.2 p  = 0.0009）。在未调整和调整的模型中，使用交联聚乙烯和 Delta-on-Delta 关节的轴承的脱位翻修率相似。

结论

带有传统聚乙烯的轴承更容易发生脱位。目前采用的轴承对因错位而导致的修正没有显着影响。这些发现可能主要与磨损有关，但由于时间分布，软组织包膜和表面张力也可能起作用。临床前生物力学评估和前瞻性匹配队列研究需要得出明确的结论。