TP7.3 Ultrasonography as an Effective First-Line Imaging Modality for Hip Abductor Tendon Pathology: A Retrospective MRI Concordance Study

Abstract

Abstract Objective To evaluate diagnostic agreement between ultrasonography (US) and magnetic resonance imaging (MRI) in suspected hip abductor pathology, and to assess the impact of body mass index (BMI) on this agreement. Methods From September 1, 2005, to March 11, 2025, patients evaluated for lateral hip pain at a single institution were retrospectively identified. Inclusion criteria were availability of both US and MRI of the same hip within a 6-month interval. Fellowship-trained musculoskeletal radiologists reviewed all imaging studies and authors classified the gluteus medius and minimus as no tear (normal/tendinosis), partial-thickness tear, or full-thickness tear. Agreement between US and MRI was assessed using weighted Cohen’s kappa, with subgroup analysis by BMI (<25 vs ≥25 kg/m2) and logistic regression modeling BMI as a continuous predictor. Results 255 hips from 241 patients were evaluated (mean age 55.2 ± 16.3 years [range, 18–94]; mean BMI 27.5 ± 6.0 kg/m2 [range, 17.0–56.2]). Agreement between US and MRI was near-perfect when combining the gluteus medius and minimus (κ = 0.95). BMI did not significantly impact agreement when analyzed categorically (<25 vs ≥25 kg/m2; κ = 0.97 vs 0.94; z = 1.24; p = 0.22) or continuously (OR per 1 kg/m2 = 0.96; 95% CI 0.88–1.04; p = 0.32). Conclusion US and MRI demonstrated near-perfect overall concordance for categorizing hip abductor tendon status in this retrospective cohort, and BMI was not associated with a statistically significant change in US–MRI agreement. These findings support US as an effective initial modality in appropriately selected patients, with MRI serving an important complementary role when higher anatomic detail is required.