Introduction: There is no consensus about what constitutes the most appropriate patient-reported outcome measurement (PROM) instrument for measuring physical function in patients with rheumatic hand conditions. Existing instruments lack psychometric testing and vary in feasibility and their psychometric qualities. We aim to develop a PROM instrument to assess hand-related physical function in rheumatic hand conditions. Methods and analysis: We will perform a systematic search to identify existing PROMs to rheumatic hand conditions, and select items relevant for hand-related physical function as well as those items from the Patient Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF) item bank that are relevant to patients with rheumatic hand conditions. Selection will be based on consensus among reviewers. Content validity of selected items will be established through the use of focus groups. If patients deem necessary, we will develop new items based on the patients' input. We will examine whether it is valid to score all selected and developed items on the same scale as the original items from the PROMIS PF item bank. Our analyses will follow the methods used for calibrating the original PROMIS PF item bank in US samples, which were largely based on the general PROMIS approach. Ethics and dissemination: This study will be carried out in accordance with the Helsinki Declaration. Ethics approvals will be obtained where necessary, and signed informed consent will be obtained from all participants. We aim to disseminate the results of the study through publication in international peer-reviewed journals and at international conferences.
