BACKGROUND: The Achilles tendon Total Rupture Score (ATRS) is a commonly used patient-reported outcome measure for patients with an acute Achilles tendon rupture. The score consists of 10 questions, the last 3 of which include activities that some patients cannot or do not do. No instruction manual has been developed for the ATRS.

HYPOTHESIS/PURPOSE: The purpose was to evaluate the ATRS at 4, 12, and 24 months after a rupture. The hypothesis was that the results at 4 months would be inconsistent when compared with the results at 1 year and 2 years. We also aimed to develop a manual that explains how to use the ATRS.

STUDY DESIGN: Cohort study (Diagnosis); Level of evidence, 3.

METHODS: This was a mixed-methods study. The first section was a registry study, where prospectively collected data were analyzed. Data were collected 4, 12, and 24 months after rupture. The original score based on 10 items was compared with a score based on the first 7 items adjusted to the same scale as the original score. Density plots and scatterplots were made and differences between the scores were tested using the Mann-Whitney U test. The second section of the study consisted of discussions among the authors, which resulted in a manual for the ATRS.

RESULTS: In total, 2790 complete ATRSs were included. The 7-item score significantly overestimated the value of the 10-item score at all time points (P < .001), but only at 4 months was the difference clinically relevant (9.7 points).

CONCLUSION: When the ATRS is used for short-term evaluation, there is a risk of results being inconsistent because of the last 3 questions. A manual explaining how to use the ATRS was therefore developed. We recommend that the full ATRS together with the manual should be used in future research rather than eliminating the 3 last questions.