Ischiofemoral Impingement: Morphologic Associations, Pelvic Asymmetry, and Clinical Correlates in a Retrospective Observational Study.

Abstract

Rationale and objectives: To investigate the association between quadratus femoris edema (QFE) and pelvic morphometric measurements, pathological findings, and pain in adults with narrowed ischiofemoral space (IFS), and to evaluate whether right-left asymmetry in pelvic morphology influences QFE development.

Methods: This retrospective single-center study included 116 adults (mean age: 54.2 years; 88.8% female) who underwent bony pelvis MRI between January 2020-June 2025 and had IFS < 15 mm. Exclusion criteria included hip surgery, femoral avascular necrosis, pediatric hip disorders, post-traumatic deformities, and nondiagnostic examinations. MRI assessments included QFE, IFS, quadratus femoris space (QFS), ischial angle, intertuberous distance, femoral neck angle, and hamstring tendon area, as well as the presence of femoroacetabular impingement, labral tears, hamstring tendinosis.

Results: QFE was present in 97 patients (83.6%). IFS and QFS were significantly smaller in edema-positive patients (p<0.001), with large-to-moderate effect sizes. Left femoral neck angle was modestly but significantly higher in the edema group (p=0.016), while other morphometrics showed no significant differences. Left-sided hamstring tendinosis was the only pathological finding associated with QFE (p=0.019). Pain was common (86.2%) but not correlated with QFE (p>0.05). Right-left asymmetry was significantly greater for QFS (p=0.005) and ischial angle (p=0.012) in patients with QFE compared to those without QFE.

Conclusion: QFE is strongly linked to reduced IFS, QFS and to asymmetries of QFS, ischial angle, but not consistently to pain. This is the first study to explore the correlation between hip pain and QFE in adults as well as role of morphometric asymmetry in QFE development highlighting the value of bilateral assessment.