Hemophilia is a rare hematological disorder characterized by a partial or complete deficiency of clotting factor VIII or IX.Bleeding disorders mainly affect the musculoskeletal system. Intra-articular bleeding is an important complication related to hemophilia and usually occurs in large synovial joints such as knees and ankles. Initially, these bleeds occur non-specific spontaneously and usually affect one joint, and repeated bleeding makes that joint a target joint. Postural balance can be defined as the ability to maintain a stable posture for maximum duration with minimal body sway, or to hold the body centre of gravity (CoG) over its base support in varying conditions (1). Somatosensorial information from mechanoreceptors, visual and vestibular receptors is required to maintain postural balance. Postural balance is tried to be controlled by the postural adjustments provided by the contraction of the lower limb muscles and trunk muscles before perturbation. Spontaneous hemarthrosis is a distinctive feature of severe haemophilia, and that recurrent bleedings may likely to cause postural balance disorders by disrupting proprioceptive inputs from mechanoreceptors in the joint. Data on how bleeding affects postural balance in children with hemophilia is unclear.In the relationship between the clinical evaluation of hemophilia and postural balance, there is little research in the literature.

The aim of this study was to investigate the changes in static postural balance parameters more reliably and comprehensively with a longer test duration and to reveal the relationship between balance parameters and joint health score in children with hemophilia. The investigator's hypothesis was that in children with hemophilia (CwH), postural balance was correlated with joint health status and had poor static postural balance compared to healthy peers.

Twenty-one CwH aged 6 to 18 years who developed hemophilic arthropathy in at least one of the lower limb joints due to severe hemophilia and twenty-one healthy peers were included in the study.

The Hemophilia Joint Health Score (HJHS), a valid and reliable test, was used to measure the joint health in CwH. Muscle strengths were measured with digital dynamometer. The kinetic devices most commonly used to evaluate in the laboratory evaluation of postural balance are the force platform and are considered the gold standard method. In the postural balance evaluation, changes in the X and Y axis were used. The amplitude of these changes, the standard deviation of the displacement, and the velocity were evaluated. In addition, the ellipse area and perimeter were measured.

Inclusion Criteria:

• Aged 6 to 18 years
• Participants do not perform regular physical activity and sports.
• For hemophilia group who developed hemophilic arthropathy in at least one of the lower limb joints due to severe hemophilia (total lower limb hemophilia joint health score ≥3).
• For hemophilia group patients to be receiving prophylaxis but have no major bleeding that could affect the musculoskeletal system in the past two weeks

Exclusion Criteria:

• Have any auditory and visual impairment
• Undergo any orthopedic injuries including lower limb
• Have any neurological or cognitive disorders

Hemophilic children in Van province