Prevalence and risk factors for Achilles tendon rupture in the military population from 2006 to 2015: A retrospective cohort study

Introduction: 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. The purpose of this retrospective cohort study was to evaluate the prevalence and associated factors of ATR in US military service members. Methods: The Defence Medical Epidemiology Database was used to identify all diagnosed ATR in military personnel from 2006 to 2015. The prevalence of ATR was calculated and compared by year, service branch and military rank. Unadjusted and adjusted assessments of 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 mechanised/armour 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. These findings highlight the populations that can most greatly benefit from preventive screening and care.