Ultrasound represents a promising technique for the assessment of joint health in persons with haemophilia (PWH) by non-imaging specialists. The Haemophilia Early Arthropathy Detection with Ultrasound (HEAD-US) programme has been developed with the aim of integrating joint ultrasound in the routine assessment of PWH through the use of a simplified scoring system. The inter-operator reliability of the technique among European haemophilia treaters has been validated and described elsewhere. Further work is needed to assess the real-world impact of ultrasound on disease management and treatment decision-making.

Patients are seen routinely in clinic by specialist haemophilia physiotherapists who assess the patients using the Haemophilia Joint Health Score tool (HJHS). Trial participants will be seen during their routine clinic visits and will be seen by a clinician and the physiotherapist who will carry out the routine assessment along with the HEAD-US scan.

Patients will be seen a maximum of 4 times throughout the year from registration of the first patient, according to their visit schedule, but will only be scanned at the first visit.

Results will be analysed to determine if the treatment decision-making is influenced by the results of the scan

Inclusion Criteria:

• Moderate (FVIII/FIX:C 1-5%) and severe (FVIII/FIX: C <1%) patients with haemophilia A or B aged ≥ 6 years
• On demand or prophylaxis treatment regimen

Exclusion Criteria:

• Joints with a previous history of surgery
• Joints with damage as a result of causes other than haemophilia-related bleeding

Data will be analysed and reported as results not individual data