Even with modern treatments, athletes with hemophilia can still develop joint damage that routine clinic exams may not fully detect. This study will test whether two imaging methods, standing CT scans and ultrasound, can better show early joint changes, and how joint health differs between athletes who take regular preventive treatment and those who do not. Standing, low dose CT scans create detailed 3D pictures of the joints while the athlete is standing, showing how the bones and joint space look under real life load. Ultrasound allows quick imaging in the clinic and can detect early joint inflammation and other soft tissue changes during sports rehabilitation visits.
We will compare how well ultrasound and weight bearing CT detect joint damage in athletes with hemophilia. We expect that weight bearing CT will be better at picking up small, early structural changes, that athletes on prophylaxis will have less joint damage on both tests, and that ultrasound will agree closely enough with weight bearing CT to be used as a practical screening tool in the hemophilia clinic. Aim 1a: Test how closely ultrasound and weight bearing CT agree when rating joint damage in ankles and knees, using CT as the main reference. Aim 1b: Compare joint damage between athletes on versus off prophylaxis, using both imaging methods and their factor trough levels. Aim 2: See how realistic and useful it is to add a brief, standardized ultrasound exam to routine sports physical therapy visits.