BACKGROUND AND PURPOSE Dislocation of a hip prosthesis is the 3rd most frequent cause (after loosening and infection) for hip revision in Norway. Recently there has been a shift in surgical practice including preferred head size, surgical approach, articulation, and fixation. We explored factors associated with the risk of revision due to dislocation within 1 year and analyzed the impact of changes in surgical practice. PATIENTS AND METHODS 111,711 cases of primary total hip arthroplasty (THA) from the Norwegian Arthroplasty Register were included (2005-2019) after primary THA with either 28 mm, 32 mm, or 36 mm femoral heads, or dualmobility articulations. A flexible parametric survival model was used to calculate hazard ratios for risk factors. Kaplan-Meier survival rates were calculated. RESULTS There was an increased risk of revision due to dislocation with 28 mm femoral heads (HR 2.6, 95% CI 2.0-3.3) compared with 32 mm heads. Furthermore, there was a reduced risk of cemented fixation (HR 0.6, CI 0.5-0.8) and reverse hybrid (HR 0.6, CI 0.5-0.8) compared with uncemented. Also, both anterolateral (HR 0.5, CI 0.4-0.7) and lateral (HR 0.6, CI 0.5-0.7) approaches were associated with a reduced risk compared with the posterior approach. The time-period 2010-2014 had the lowest risk of revision due to dislocation. The trend during the study period was towards using larger head sizes, a posterior approach, and uncemented fixation for primary THA. INTERPRETATION Patients with 28 mm head size, a posterior approach, or uncemented fixation had an increased risk of revision due to dislocation within 1 year after primary THA. The shift from lateral to posterior approach and more uncemented fixation was a plausible explanation for the increased risk of revision due to dislocation observed in the most recent time-period. The increased risk of revision due to dislocation was not fully compensated for by increasing femoral head size from 28 to 32 mm.

中文翻译：

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2005 年至 2019 年 111,711 例初次全髋关节置换术后一年内因脱位而进行翻修手术的危险因素：来自挪威关节置换术登记处的一项研究。


背景和目的 在挪威，髋关节假体脱位是髋关节翻修的第三大常见原因（仅次于松动和感染）。最近，手术实践发生了变化，包括首选的头部尺寸、手术方法、关节和固定。我们探讨了与一年内脱位翻修风险相关的因素，并分析了手术实践变化的影响。患者和方法 挪威关节置换术注册中心 (2005-2019) 纳入了 111,711 例初次全髋关节置换术 (THA) 病例，这些病例在初次全髋关节置换术后采用 28 mm、32 mm 或 36 mm 股骨头或双活动关节。使用灵活的参数生存模型来计算危险因素的风险比。计算了卡普兰-迈耶存活率。结果 与 32 mm 股骨头相比，28 mm 股骨头脱位导致翻修的风险增加（HR 2.6，95% CI 2.0-3.3）。此外，与未骨水泥固定相比，骨水泥固定（HR 0.6，CI 0.5-0.8）和反向混合固定（HR 0.6，CI 0.5-0.8）的风险降低。此外，与后入路相比，前外侧入路（HR 0.5，CI 0.4-0.7）和侧入路（HR 0.6，CI 0.5-0.7）均与风险降低相关。 2010-2014 年期间因错位而导致翻修的风险最低。研究期间的趋势是采用更大的头部尺寸、后路入路和非骨水泥固定进行初次 THA。解释 头颅大小为 28 mm、后路入路或非骨水泥固定的患者初次 THA 后 1 年内因脱位而翻修的风险增加。 从外侧入路到后路入路的转变以及更多的非骨水泥固定是最近一段时间观察到的脱位导致翻修风险增加的合理解释。由于脱位而增加的翻修风险并不能通过将股骨头尺寸从 28 毫米增加到 32 毫米来完全补偿。