Imaging study of hidden bleeding in knee joint of hemophilia patients

Background. Hemophilia is the most prevalent severe inherited bleeding disorder, affecting an estimated 1 in 10,000 live births. Over 1,500 individuals in Iraq have hemophilia. Radiology is crucial in evaluating knee hemarthrosis in hemophilia. This study aimed to compare the accuracy of ultrasonography (US) and magnetic resonance imaging (MRI) in detecting hemophilic changes in knee joints. Methods. A cross-sectional study included 36 hemophilia patients –30 males (83.3%), mean age 9.81 years, and 6 females (16.7%), mean age 3.86 years), who attended the Department of Radiology, Al-Hilla General Hospital from July 26, 2023, to May 29, 2024. Ultrasonography was used to asses synovial thickness, cartilage thickness, vascularity, effusion and joint bleeding, while MRI allowed the assessment of joint effusion, synovial hypertrophy, hemosiderin deposits, surface erosions, subchondral cysts and cartilage degradation. Data included age, sex, hemophilia severity, and joint involvement. Results. The right knee was most affected in 23 patients (63.9%). Moderate hemophilia accounted for 63.9% of cases (23 patients), while severe hemophilia comprised 36.1% (13 patients). US detected synovial thickness in 8.3% (3 patients), elevated vascularity in 25.0% (9 patients), and effusion in 13.9% (5 patients). MRI showed effusion in 33.3% (12 patients), synovial hypertrophy in 11.1% (4 patients), surface erosions in 8.3% (3 patients), and extension of supra patellar in 11.1% (4 patients). Gender had a direct impact on synovial thickness in US (OR=16.0, P=0.027) and extension of the suprapatellar region in MRI (OR=8.0, P=0.008). The right knee joint was a significant predictor in MRI findings: effusion (OR=4.2, P=0.05), surface erosion (OR=11.3, P=0.015), and extension of the suprapatellar region (OR=6.6, P=0.012). MRI had higher sensitivity (91.67% vs. 86.11%) but lower specificity (81.11% vs. 83.33%) compared to US. MRI was more accurate overall (89.72%, P<0.0001). Conclusions. The pediatric age group, male gender, and right-sided joint involvement were the most common features of hemophilic changes. US is cost-effective and specific for detecting synovial thickening, elevated vascularity, and joint effusion. Gender and knee joint side directly impact the findings of US and MRI in patients with hemophilia. MRI excels in sensitivity and accuracy for joint effusion and erosions. Both modalities complement each other in managing hemophilic knee changes.