Background: Achilles tendon rupture (ATR) is a serious musculoskeletal injury that results in substantial functional decline, especially in highly physically demanding occupations such as service in the military Purpose: The objective of this study was to evaluate the burden and associated factors of ATR in US military service members. Study Design: Descriptive Epidemiology Study Methods: The Defense Medical Epidemiology Database was used to identify all diagnosed ATR in military personnel from 2006 to 2015. Prevalence of ATR was calculated and compared by year, service branch, and military rank. Unadjusted and adjusted assessments of injury risk were calculated. Results: Officers incurred 15 978 episodes at a prevalence of 7.43/1000 (male: 8.11/1000; female: 3.89/1000). Among enlisted personnel, there were 59 242 episodes of ATR that occurred at a prevalence of 6.23 episodes per 1000 (male enlisted: 6.49/1000; female enlisted: 4.48/1000). Apart from enlisted aviation specialists (where there was no significant difference in risk between men and women), both female officers and enlisted service members had significantly lower risk of ATR compared with their male counterparts in all occupations (prevalence ratio [PR]: 0.26-0.73). Aviation and service officers demonstrated significantly lower risk of ATR episodes (PR: 0.87-0.91) and administration, operations, intelligence, and logistic officers demonstrated increased risk (PR: 1.16-1.31) compared with ground and naval gunfire officers. Among enlisted specialties, all but mechanized/armor and combat engineers had significantly higher risk of ATR risk compared with infantry (PR: 1.14-2.13), with the highest risk observed in the administration, intelligence, and communication fields. Conclusions: ATR was ubiquitous in the US military, with multiple risk factors identified, including male sex, older age, rank, military occupation, and service branch. Clinical Relevance: Based on the burden of ATR in the US military observed in this study, these findings highlight both the need for prophylactic interventions and identification of the populations who can most greatly benefit from preventive screening and care.

Disclaimer: JJF, CKS, and CJF are military service members or employees of the U.S. Government. This work was prepared as part of their official duties. Title 17, U.S.C. SS105 provides that copyright protection under this title is not available for any work of the U.S. Government. Title 17, U.S.C. SS101 defines a U.S. Government work as work prepared by a military service member or employee of the U.S. Government as part of that person's official duties. The views expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, nor the U.S. Government. Author Contributions: JJF, JAZ, and CKS contributed to the drafting of this manuscript. JJF contributed to the conception, study design, data acquisition, and analysis. All authors contributed to data interpretation, critical revision, and final approval of the study. Conflict of Interest Statement: Dr. Fraser reports grants from Congressionally Directed Medical Research Programs and the Office of Naval Research, outside of the submitted work. In addition, Dr. Fraser has a patent pending for an Adaptive and Variable Stiffness Ankle Brace, U.S. Provisional Patent Application No. 63254,474.

This study did not receive any funding

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The study protocol was approved by the Naval Health Research Center Institutional Review Board in compliance with all applicable federal regulations governing the protection of human subjects. Research data were derived from approved Naval Health Research Center Institutional Review Board protocol, number NHRC.2020.0207-NHSR

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