Iliopsoas Cross-Sectional Area at the Psoas Valley is Associated with Surgically Treated Femoroacetabular Impingement Syndrome: A CT-based Case–Control Study

Introduction: The iliopsoas muscle passes immediately anterior to the hip joint and lies in close proximity to the acetabular labrum at the level of the psoas valley. This anatomical relationship suggests that local muscle morphology may be associated with symptomatic hip pathology. The present study investigated the association between iliopsoas cross-sectional area at the psoas valley, adjacent osseous morphology, and surgically treated symptomatic hip-pathologies. Methods: In this retrospective case–control study, 92 adult patients who underwent hip arthroscopy between 2019 and 2024 and had preoperative computed tomography (CT) imaging were compared with 50 age- and sex-matched controls without documented hip pain who had CT scans obtained for non-hip-related indications. Three-dimensional CT reconstructions were used to measure retroinguinal and psoas-valley morphometric parameters, including iliopsoas crosssectional area at the level of the psoas valley. Multivariable logistic regression adjusted for age and body mass index was performed for variables that differed between groups. Results: The groups did not differ significantly in age, sex, body mass index, or side. The lacuna musculorum ratio was higher in the surgical cohort than in controls (0.5 ± 0.1 vs. 0.4 ± 0.1; p < 0.001). Iliopsoas cross-sectional area at the psoas valley was smaller in the surgical cohort (12.5 ± 3.2 cm2 vs. 13.7 ± 2.8 cm2; p = 0.025). In multivariable analysis, a higher lacuna musculorum ratio (OR:1.094, 95% CI 1.026–1.167; p = 0.006) and a smaller iliopsoas cross-sectional area (OR:0.998, 95% CI 0.996–1.000; p = 0.039) remained associated with membership in the surgically treated cohort. Conclusion: Smaller iliopsoas cross-sectional area at the psoas valley was more often associated with surgically treated hip pathologies. These findings support a possible anatomical relationship between anterior hip soft-tissue morphology and symptomatic hip pathology, but they do not establish a protective causal effect of greater iliopsoas muscle bulk against labral injury.