Retrospective Comparison of Musculoskeletal Ultrasound and Magnetic Resonance Imaging for Detecting Hemophilic Arthropathy.

Hemophilic arthropathy is a major cause of morbidity in patients with hemophilia, resulting from recurrent joint bleeding and progressive synovial and osteochondral damage. Although magnetic resonance imaging (MRI) is the reference standard for evaluating hemophilic joints, its routine use is limited by cost and accessibility. Musculoskeletal ultrasound (MSK-US) has emerged as a practical alternative; however, its diagnostic performance relative to MRI requires further evaluation. The objective of this study is to evaluate the diagnostic accuracy of MSK-US for detecting hemophilic arthropathy using MRI as the reference standard. This retrospective diagnostic accuracy study included 150 patients with hemophilia who underwent both MSK-US and MRI of the same joint within a three-month interval. Ultrasound positivity was defined as the presence of at least one abnormal feature (synovial hypertrophy, joint effusion, cartilage damage, or bone erosion). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), likelihood ratios, and Cohen's kappa were calculated. ROC analysis was performed using HEAD-US scores. MSK-US demonstrated a sensitivity of 91.1%, specificity of 78.9%, PPV of 92.7%, NPV of 75.0%, and overall accuracy of 88.0%. Agreement with MRI was good for synovial hypertrophy (κ = 0.72) and joint effusion (κ = 0.69), and moderate for cartilage damage (κ = 0.58) and bone erosion (κ = 0.55). ROC analysis showed good overall diagnostic performance (AUC = 0.86; 95% CI, 0.80-0.91). Diagnostic performance was highest for synovial abnormalities and lower for structural joint damage. MRI-confirmed arthropathy was present in 74.7% of patients, reflecting a selected cohort with a high prevalence of joint pathology. In this selected retrospective cohort, MSK-US demonstrated good diagnostic performance for detecting hemophilic arthropathy, particularly synovial abnormalities. MSK-US may serve as a complementary tool for clinical assessment, triage, and longitudinal monitoring, while MRI remains important for comprehensive evaluation of structural joint damage.