Early diagnosis and rapid treatment initiation are of most importance to prevent joint damage in patients with arthritis. Musculoskeletal ultrasound (MSUS) is becoming an integrated part of rheumatology routine care and is more sensitive than clinical examination for detecting synovitis even in the early stage of disease.

However, MSUS is highly operator dependent and competences are needed to ensure correct image interpretation. Traditionally competences are evaluated on how many examinations the trainees have performed, but the gold standard has now shifted towards competency-based education where objective assessment tools are the key element. A previous study has developed a scale for assessment of ultrasound competence, The Objective Structured Assessment of Ultrasound skills (OSAUS). Although expert consensus supports evidence of content validity of the assessment instrument, it is not known if the OSAUS scale can discriminate differences in performance scores between different levels of MSUS experience in rheumatology in a reliable way.

Inclusion Criteria:

• Physicians working at the rheumatology departments in Denmark:

  1. Novices: No or little experience with MSUS (less than 100 examinations).
  2. Intermediates: Participated and completed at least one formal ultrasound course and more than 100 examinations (less than 1000 MSUS examinations).
  3. Physicians with a long experience in MSUS doing the procedure almost daily and providing teaching and/or research within this field (more than 1000 examinations).

Exclusion Criteria:

• No informed consent
• Novices/Intermediates: extensive experience in MSUS