Translation, cultural adaptation and validation of the Achilles Tendon Total Rupture Score (ATRS) into Spanish: a study protocol.

The Achilles tendon is the strongest and largest tendon in the human body, yet it is also the most frequently ruptured. The incidence of Achilles tendon rupture (ATR) is increasing due to an ageing population, rising obesity rates and greater sports participation. The Achilles Tendon Total Rupture Score (ATRS) is a validated patient-reported outcome measure widely used to assess clinical and functional outcomes after ATR. However, there is no culturally adapted and validated Spanish version of this tool, limiting its applicability in Spanish-speaking populations. The aim is to translate, culturally adapt and validate the Spanish version of the ATRS following international guidelines and to analyse its psychometric properties for assessing clinical and functional outcomes in patients with ATR. This study protocol outlines a cross-sectional design adhering to Strengthening the Reporting of Observational Studies in Epidemiology and Checklist for Reporting Results of Internet E-Surveys guidelines for observational studies and online surveys. The ATRS will be translated and culturally adapted, psychometric analysis will follow COnsensus-based Standards for the selection of health Measurement INstruments standards, including reliability, validity and sensitivity assessments. Participants will include patients treated surgically for ATR in hospitals across Madrid and healthy controls recruited through social media. Sociodemographic, clinical and functional data will also be collected to support the validation process. This study protocol was approved by the Universidad Europea de Madrid Institutional Board (Approval ID: CI 2024/897) prior to data collection based one the Declaration of Helsinki. The study's findings will be distributed to athletes, physicians and academics via peer-reviewed publications and national/international conferences.