RecruitingDrug trialTG-INSIGHT With Joint POCUS, Hemostatic Potential in Patients With Severe Hemophilia A on Novel Replacement and Substitution FVIII TherapiesThis is an observational research study to find out if there is a difference in the way children with moderate or severe hemophilia A, treated on two different types of factor replacement, form a clot and also evaluate if they develop tiny bleeds within the joint and subsequently early joint changes when receiving extended half-life factor VIII.