Summary: This retrospective/prospective, non-randomized controlled study, whereby patients will be included in 1 of 2 groups depending on their current treatments as outlined below. Patients will be assigned to a specific group by the clinician/PI based on their current regimen with the intent to stay on this regimen for the next 3 years.
Duration of Study and Subject Participation: Study subject enrollment is anticipated to occur over about 12 months and study duration per subject will be 3 years. Thus a total study duration of 4 years is anticipated.
Intervention: By using musculoskeletal ultrasound, the investigators will measure joint health among participants and assess joint health changes over 3 years compared between group A (factor prophylaxis) vs. group B (emicizumab prophylaxis) as assessed by MSKUS at baseline and after 3 years. Other outcomes such as bone density, comparative assessment of joint and overall health status, and exploration of potential biomarkers for joint and bone health will also be assessed.
