TENDINopathy Severity Assessment - Patellar (TENDINS-P): Development and Content Validity Assessment of a New Patient-Reported Outcome Measure for Patellar Tendinopathy.

OBJECTIVES: To (1) collate current practice, perceptions, and experience of patients and professionals to develop a patient-reported outcome measure (PROM) that assesses the severity of disability in patellar tendinopathy, and (2) evaluate the content validity (relevance, comprehensiveness, and comprehensibility) of the developed PROM. DESIGN: Mixed-methods PROM development and content validation study. METHODS: Using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) methodology, we performed 1 round of semistructured, one-on-one interviews with professional (n = 8: health care providers and research experts) and patient participants (n = 7) for initial item generation. To assess content validity, we collected 1 round of survey responses for professional participants (n = 33) and conducted 1 round of semistructured, one-on-one interviews with patient participants. RESULTS: Item generation resulted in 15 items in the subdomains of pain (general), function, and pain (with loading). The 15 items were sent to professional participants, and all items reached the 0.70 item-content validity coefficient cutoff for relevance. One item was substantially lower than others and excluded. The remaining 14 items met the criteria for comprehensibility; all items had a median comprehensibility of ≥6/7 and were comprehensible. Patient participants endorsed PROM content validity. Individual completion times ranged from 4 to 9 minutes. CONCLUSION: We established the content validity of the Tendinopathy Severity Assessment - Patellar (TENDINS-P) as a new PROM to assess the severity of patellar tendinopathy. The TENDINS-P assesses aspects of pain (general), function, and pain (with loading). TENDINS-P can now be used in clinical and research populations. J Orthop Sports Phys Ther 2026;56(5):300-309. Epub 9 April 2026. doi:10.2519/jospt.2026.13984.