POCUS: Hemostatic Potential and Joint Health in Patients With Severe Hemophilia A on Novel Replacement Therapies

Inclusion Criteria: * Subjects with moderate hemophilia A (baseline factor VIII activity 1-5%) or severe hemophilia A (baseline factor VIII activity \<1%) on prophylactic standard half-life FVIII infusions OR subjects with moderate or severe hemophilia A who have not started prophylactic treatment * Less than 18 years of age Exclusion Criteria: * Subjects with documented FVIII inhibitor * Subjects with a history of ≥ 2 target joints * Subjects with a history of synovectomy * Currently using medications known to impact bone and mineral metabolism (e.g., bisphosphonates, corticosteroids, estrogen, testosterone, calcitonin, thyroid hormone therapy); * Disease states known to affect bone integrity (e.g., primary hyperparathyroidism, Paget's disease, clinically significant liver disease)