Evaluation of Joint Arthropathy Using Ultrasound Technique in Children with Severe Hemophilia Undergoing Prophylaxis Regimen: The Hemophilia Ultrasound Project HUP

Protocol Title: Evaluation of Joint Arthropathy Using Ultrasound Technique in Children with Severe Hemophilia Undergoing Prophylaxis Regimen: The Hemophilia Ultrasound Project (HUP Study) Objectives/Specific Aims: We are poised to establish US imaging technique as a valid method to identify early signs of hemophilic arthropathy in clinically asymptomatic joints never affected by overt bleeding events, and to follow the natural evolution of these same joints in both severe hemophilia pediatric patients on prophylactic infusion regimens and in mild/moderate hemophiliac patients without evidence of a target joint or a history of overt joint bleeds. We hypothesize that these early-onset subclinical joint alterations, whereas not easily detectable at the clinical examination, could be identified and followed by US examination using a previously validated US score . Our specific aims are as follows: Specific Aim 1: To evaluate the prevalence of subclinical arthropathy in children with severe hemophilia undergoing a prophylaxis regimen and without evidence of target joints, using a validated ultrasound scoring method. Specific Aim 2: To monitor the natural progression of subclinical joint changes (including but not limited to synovial changes, joint effusion, synovitis, cartilage damage and subchondral bone damage) in hemophilic children undergoing prophylaxis regimen over an extended period of time (5 years). Specific Aim 3: To compare the differences of joint characteristics in between the study population and previously reported data from healthy age-matched pediatric patients. Specific Aim 4: To evaluate the prevalence of subclinical arthropathy in children with mild and/or moderate hemophilia using a validated ultrasound scoring method and to monitor the natural progression of subclinical joint changes (including but not limited to synovial changes, joint effusion, synovitis, cartilage damage and subchondral bone damage), and by extension, to begin to ascertain a minimum protective factor level. Specific Aim 5: To compare the characteristics of subclinical joint changes (time of presentation, natural evolution, etc.) in between patients with severe hemophilia and those with mild/moderate hemophilia.