Risk Factors for Iliopsoas Impingement Following Total Hip Arthroplasty: A Systematic Review

Background: Iliopsoas impingement (IPI) is an increasingly recognized cause of persistent groin pain following total hip arthroplasty (THA), often resulting from mechanical conflict between the iliopsoas tendon and the anterior rim of the acetabular component. Despite its clinical relevance, risk factors contributing to IPI remain poorly defined. Methods: A systematic search of PubMed, Embase, Scopus, and the Cochrane Library was conducted according to PRISMA guidelines. Studies were eligible if they evaluated adult patients undergoing primary THA and reported at least one risk factor associated with IPI. Only studies with a clearly defined clinical diagnosis of IPI were included. Data extraction and risk of bias assessments were performed independently by two reviewers. Risk of bias in each study was assessed through the Newcastle-Ottawa Scale. Results: Twelve observational studies met the inclusion criteria. Diagnosis of IPI was based on clinical symptoms of anterior groin pain exacerbated by hip flexion; 9 studies confirmed diagnosis with anesthetic injections. Key surgical risk factors included anterior cup prominence (ORs 1.16-35.20), oversized cups (cup-to-head ratio > 1.2, OR = 5.39, or ≥6 mm difference, OR = 26.00), decreased cup inclination, collared stem protrusion (OR = 13.89), and acetabular screw protrusion > 6.4 mm. Patient-specific risk factors included female sex (ORs 2.56, 2.79), higher BMI (OR = 1.07), younger age, previous hip arthroscopy (OR = 9.60) and spinal fusion (OR = 4.60). The anterolateral approach was also associated with higher IPI risk when compared to the posterior approach (OR = 4.20). Conclusions: IPI after THA is a multifactorial complication influenced by modifiable surgical variables and patient-specific anatomy. Careful preoperative planning, precise implant positioning, and attention to individual risk factors are essential to reduce IPI incidence and improve outcomes.