Validity and reliability of the Norwegian translation of the Achilles tendon Total Rupture Score.

Purpose: Patient reported outcome measures (PROMs) are increasingly being used in clinical research. The Achilles tendon Total Rupture Score (ATRS) is a PROM designed to assess outcomes in patients with ruptures of the Achilles tendon. The aim of this study was to develop a Norwegian adaption of the ATRS and evaluate its validity and reliability.

Methods: The ATRS was translated into Norwegian in accordance with recommended guidelines. The study included 94 patients treated for Achilles tendon ruptures from January 2010 until February 2013, and the web-based questionnaires were administered twice. Reliability was assessed by Cronbach's alpha, the intraclass correlation coefficient (ICC) and minimal detectable change (MDC). Construct validity was evaluated by calculating the Spearman's correlation coefficient with the five subclasses of the Foot and Ankle Outcome Score (FAOS), the SF-36 subclass physical function and the SF-36 physical and mental summary scores.

Results: Both internal consistency (Cronbach's alpha = 0.96) and test-retest reliability (ICC = 0.90) were excellent, and the MDC was 2.12 at the group level and 16.98 at the individual level. Construct validity was supported by Spearman's correlation coefficients above 0.7 with the SF-36 subclass physical function and the SF-36 physical summary score as well as the FAOS subclasses Sport/Rec and quality of life. There was no floor effect, and 6 patients (6.4%) achieved a maximum score of 100.

Conclusions: The Norwegian adaption of the ATRS demonstrates acceptable validity and reliability for use in the Norwegian population to assess clinical outcomes in patients with Achilles tendon ruptures.