Extraarticular and Intraarticular Key Lesions in Knee Joints of Adult Persons with Hemophilia—A Case-Control Ultrasound Study

Abstract Background: Persons with hemophilia (PwH) develop arthropathic changes due to recurrent hemarthroses. This study aimed to comprehensively investigate structural knee joint alterations in PwH, extended beyond synovitis and osteochondral abnormalities, and to compare findings with healthy controls (Con). Methods: Bilateral knee ultrasound examinations were performed in 36 male PwH (severe A: 30, B: 2; moderate A: 3, B: 1; mean age: 47.1 ± 12.0) and 39 age-matched Con (mean age: 47.7 ± 12.8). A total of 26 landmarks and tissues, including synovium, osteophytes, ligaments, tendons, and bursae, were assessed quantitatively or semi-quantitatively. Clinical joint status was classified using the Hemophilia Joint Health Score, distinguishing between minorly (PwH-MI) and majorly (PwH-MA) affected joints. Results: Synovium, osteophytes, ligaments, and bursae showed more pronounced alterations in PwH compared to Con. While the iliotibial band was slightly thicker in PwH (p = 0.023), the popliteus tendon (p = 0.001) and patellar tendon at the tibial insertion were significantly thinner. PwH-MA showed significant changes at all landmarks (p < 0.001), while PwH-MI demonstrated differences only in the lateral knee joint synovium (p = 0.006) compared to Con. Osteophytes and synovium were significantly thicker in PwH-MA than in PwH-MI. Conclusion: The findings highlight the importance of assessing periarticular structures in PwH, as changes may contribute to functional impairments such as gait deviations. Further research is required to clarify the clinical implications.