Burden and risk factors for achilles tendinopathy in the military population, 2006-2015: A retrospective cohort study

Abstract: Context: Ankle-foot injuries are ubiquitous in the US military, with Achilles tendinopathy a common condition that affects function and health-related quality of life. Objective: To evaluate the burden and associated factors of Achilles tendinopathy. Design: Descriptive epidemiology study. Setting: The Defense Medical Epidemiological Database was used to identify relevant health care encounters. Patients or other Participants: All active duty and reserve military members who served between 2006 and 2015 (officers = 2 149 887; enlisted = 9 503 995). Main Outcome Measures: Multiyear prevalence of Achilles tendinopathy care episodes was calculated and compared by military rank, service branch, and year. Unadjusted and adjusted assessments of injury burden were calculated. Results: Officers incurred 37 939 episodes at a prevalence of 17.65 per 1000 servicemembers (male officers = 18.20 per 1000 servicemembers, female officers = 14.80 per 1000 servicemembers). Among enlisted personnel, 116 122 episodes of Achilles tendinopathy occurred in 12.22 per 1000 servicemembers (male enlisted = 12.07 per 1000 servicemembers, female enlisted = 13.22 per 1000 servicemembers). All officer specialties had a higher burden of Achilles tendinopathy episodes than the ground and naval gunfire officers (prevalence ratio [PR] = 1.04-1.43) except for aviation, which demonstrated a lower burden (PR = 0.65). Among enlisted occupations, maritime or naval specialties had a lower burden of Achilles tendinopathy than infantry (PR = 0.82) and all other specialties except for aviation, which had a higher burden (PR = 1.07-1.71). Multiple associated factors were identified: sex, age, rank, military occupation, and service branch. Conclusions: Achilles tendinopathy was ubiquitous in the US military, with a progressive increase in prevalence during the study epoch. Sex, age, rank, military occupation, and service branch were identified as associated factors. These findings highlight the need for both prophylactic interventions and identification of the populations with the greatest need.