Abstract
BackgroundThe 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.MethodsA 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.ResultsAt 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.ConclusionsThe 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 of evidenceLevel IV, clinical cohort study
Highlights
Iliopsoas impingement (IPI) is one of the underrecognized causes of hip pain after primary total hip arthroplasty (THA), which is characterized by persistent groinAmong various factors contributing to IPI, the factors related to the acetabular component have been examined in previous studies, including cement extrusion [5], the penetrated screws for acetabular fixation [6] and aQiu et al Journal of Orthopaedic Surgery and Research (2020) 15:267 mal-positioned acetabular cup [7, 8], or the reinforcement ring [9]
The present study retrospectively revealed a high incidence of IPI (7.3%) in THA patients using a collared femoral prosthesis
After excluding factors related to the acetabular component and the femoral head, our study identified increased stem anteversion and collar protrusion length (CPL) as the risk factors for IPI
Summary
Iliopsoas impingement (IPI) is one of the underrecognized causes of hip pain after primary total hip arthroplasty (THA), which is characterized by persistent groinAmong various factors contributing to IPI, the factors related to the acetabular component have been examined in previous studies, including cement extrusion [5], the penetrated screws for acetabular fixation [6] and aQiu et al Journal of Orthopaedic Surgery and Research (2020) 15:267 mal-positioned acetabular cup [7, 8], or the reinforcement ring [9]. Iliopsoas impingement (IPI) is one of the underrecognized causes of hip pain after primary total hip arthroplasty (THA), which is characterized by persistent groin. A collared femoral prosthesis has been regarded as an unusual cause of IPI in only two case reports [15, 16]. In these studies, the authors reported a limited number of patients with persistent groin pain, which was all caused by the impingement between the metal collar and the iliopsoas tendon as it overhung the calcar. 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
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