Prevalence of Synovial Hypertrophy in 428 Patients with Haemophilia A

Introduction Recurrent hemarthroses lead to progressive arthropathy and disability in Patients with Haemophilia (PWH) [ 1 ]. Point-of-care musculoskeletal ultrasound (POC-US) with the standardized HEAD-US protocol provides a rapid, reproducible diagnostic tool, enabling reliable detection of synovial hypertrophy and structural damage [ 2 ] [ 3 ]. In the present study we aimed to determine the prevalence of synovial hypertrophy with its first manifestation and evaluated its associations with haemophilia severity, age, BMI and treatment regimen. Method This single-center, retrospective study included 428 PWH managed at the Hemophilia Center Bonn between 2022 and 2025. A trained physician performed POC-US examinations of elbows, knees, and ankles. We assessed and documented synovitis and arthropathy scores. Institutional records provided demographic and clinical variables, including age, BMI, haemophilia severity and prophylaxis regimen. Results A total of 428 patients were included (316 with severe, 83 with moderate, 29 with mild hemophilia A; median age 32 years, range 1–79). Synovial hypertrophy was present in 46% of patients. In total, 2,489 joints were examined, 836 ankles, 800 knees and 853 elbows. Synovial hypertrophy was detected in 228 ankle joints (27.3%), 150 knee joints (18.8%) and 178 elbows joints (20.9%), amounting to 556 joints overall and an aggregated prevalence of 22.3%. The prevalence of synovial hypertrophy for ankle, knee and elbow joints was higher in severe haemophilia A (21-32%) than in non -severe haemophilia A (7.0-15.8% )(for details see [ Fig. 1 ]). With aging, the number of joints affected increased with mean age 45.48±13.4 in the synovial hypertrophy group vs. 31.50±11.2 in the not affected group (p