Introduction Tendinopathy (local tendon pain associated with physical activity) is a challenge to treat despite recent advances. One factor contributing to this challenge is our limited ability to synthesise/meta-analyse research findings, which is further compounded by a lack of valid outcome measures. We determined the core outcome domains against which outcome measures could be recommended.

Materials and methods We conducted a Delphi study of patients and health care professionals (HCP) in two parts: an online survey and consensus meeting. Online survey items were extracted from clinical trial reports. Agree, disagree, or unsure were options in response to: ‘The ‘item’ is important enough to be included in a core domain set of tendinopathy’. A-priori criterion of ≥70% participant agreement was deemed for selection of a core domain.

Results 32 patients and 28 HCP (92% had >10 years of tendinopathy experience, 71% consulted >10 cases per month) completed the online survey. 2 patients and 15 HCP attended the consensus meeting. Of the original 24 items (from trial reports); 9 were core: Patient overall rating, participation, pain on activity/loading, disability, function, physical function capacity, quality of life, psychology, and pain over a specified timeframe. Eight items were not core domains: range of motion, palpation, clinical examination, structure, pain on examination or without other specification, drop out, and sensory modality pain. Remaining seven items did not meet criterion.

Conclusion The core domain set serves as a guide for reporting of outcomes in clinical trials. Further research should determine these outcomes for each specific tendon.