The relationship between collar design of a femoral component and iliopsoas impingement (IPI) after total hip arthroplasty (THA) is still underrecognized. The purpose of our study was to determine the possible risk factors for IPI related to the femoral component, when using a collared femoral prosthesis. A total of 196 consecutive THA patients (206 hips) using a collared femoral prosthesis were reviewed retrospectively after exclusion of the factors related to acetabular component and femoral head. The patients were divided into +IPI and −IPI group according to the presence of IPI. Radiological evaluations were performed including femoral morphology, stem positioning, and collar protrusion length (CPL). Multivariate regression analysis was performed to assess the risk factors for IPI. At a minimum follow-up of 1 year, IPI was observed in 15 hips (7.3%). Dorr type C proximal femur was found in nine hips (60%) in the +IPI group and in 28 hips in the −IPI group (14.7%, p < 0.001). The mean stem anteversion in the +IPI group was significantly greater than that in the −IPI group (19.1° vs. 15.2°, p < 0.001), as well as the mean CPL (2.6 mm vs. − 0.5 mm, p < 0.001). The increased stem anteversion (OR = 1.745, p = 0.001) and CPL (OR = 13.889, p = 0.001) were potential risk factors for IPI. The incidence of IPI after THA is higher than expected when using a collared femoral prosthesis. Among the factors related to collared femoral prosthesis, excessively increased stem anteversion and prominent collar protrusion are independent predictors for IPI. In addition, high risk of IPI should be carefully considered in Dorr type C bone, despite that femoral morphology is not a predictive factor. Level IV, clinical cohort study

中文翻译：

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使用带颈的股骨假体进行全髋关节置换后，op肌冲击的危险因素。

全髋关节置换术（THA）后，股骨组件的颈圈设计与肌冲击（IPI）之间的关系仍未得到充分认识。我们的研究目的是确定使用带颈圈的股骨假体时与股骨组件相关的IPI的可能危险因素。排除与髋臼组件和股骨头有关的因素后，回顾性分析了总共196例使用颈圈股骨假体的连续THA患者（206髋）。根据IPI的存在将患者分为+ IPI和-IPI组。进行了放射学评估，包括股骨形态，茎定位和项圈突出长度（CPL）。进行多元回归分析以评估IPI的危险因素。至少随访1年，在15髋（7.3％）中观察到IPI。+ IPI组的9髋（60％）和-IPI组的28髋（14.7％，p <0.001）发现了Dorr C型近端股骨。+ IPI组的平均茎前倾明显高于-IPI组的（19.1°vs. 15.2°，p <0.001），以及平均CPL（2.6 mm vs.-0.5 mm，p <0.001） ）。茎前倾增加（OR = 1.745，p = 0.001）和CPL（OR = 13.889，p = 0.001）是IPI的潜在危险因素。THA后IPI的发生率高于使用颈圈股骨假体时的预期。在与颈圈假体相关的因素中，茎前倾过度增加和明显的颈圈突出是IPI的独立预测因子。此外，在Dorr C型骨中应仔细考虑IPI的高风险，尽管股骨形态不是预测因素。IV级，临床队列研究