Sex and Occupation Are Salient Risk Factors for Lateral Ankle Sprain Among Military Tactical Athletes

Abstract

Introduction: Lateral ankle sprains (LAS) are ubiquitous among tactical athletes and a substantial burden in the military. With the changes in operational demand and the beginning of integration of women into previously closed occupations, an updated assessment of the burden of ankle sprains in the military is warranted. Methods: A population-based epidemiological retrospective cohort study of all service members in the US Armed Forces was performed assessing risk of sex and military occupation on the outcome of LAS incidence. The Defense Medical Epidemiology Database was queried for the number of individuals with ICD-9 diagnosis codes 845.00 (sprain of ankle, unspecified) and 845.02 (calcaneofibular ligament sprain) on their initial encounter from 2006 to 2015. Relative risk (RR) and chi-square statistics were calculated in the assessment of sex and occupational category. Results: A total of 272,970 enlisted males (27.9 per 1000 person-years), 56,732 enlisted females (34.5 per 1000 person-years), 24,534 male officers (12.6 per 1000 person-years), and 6020 female officers (16.4 per 1000 person-years) incurred LAS. Enlisted females in all occupational groups were at significantly higher risk for LAS than their male counterparts (RR 1.09-1.68; p < 0.01), except for Engineers (p = 0.15). Female officers had consistently higher risk for LAS in all occupational groups (RR 1.10-1.42; p < 0.01) compared with male officers, except Ground/Naval Gunfire (p =0.23). Contrasted with Infantry, enlisted members in the Special Operations Forces, Mechanized/Armor, Aviation, Maintenance, and Maritime/Naval Specialties were at lower risk (RR, 0.38-0.93; p < 0.01), Artillery, Engineers, and Logistics Specialties were at higher risk (RR 1.04-1.18; p < 0.01), and Administration, Intelligence, and Communications were no different (p = 0.69). Compared with Ground/Naval Gunfire officers, Aviation officers were at significantly lower risk (RR, 0.75; p < 0.01), and Engineers, Maintenance, Administration, Operations/Intelligence, and Logistics officers were at higher risk (RR, 1.08-1.20; p < 0.01). Conclusion: Sex and military occupation were salient factors for LAS risk. Colocation of interdisciplinary neuromusculoskeletal specialists to provide targeted preventive interventions should be considered in practice and policy.

Fractures and Chronic Recurrence are Commonly Associated with Ankle Sprains: a 5-year Population-level Cohort of Patients Seen in the U.S. Military Health System

“…21 In a more recent epidemiological study assessing lateral ankle sprain risk in the military, 360,256 service members incurred this injury from 2006 to 2015 at a rate of 28.8 per 1000 person-years in enlisted members and 13.2 per 1000 person-years in military officers. 5 It is therefore no surprise to see the number of service members with these injuries and the substantial burden these injuries placed on the military health system. Considering there are a large subset of service members who do not seek care for ankle sprains, the true burden is likely even larger.…”

“…4 These findings are likely attributed, in part, to footwear choices, hormonal influences, and differences in joint phenotypes observed in females. 5 This may also be attributed to greater care seeking in females, 5 a factor that is quite plausibly mediated by cultural influences in the military. 22 The mean age of this study cohort (31.7±8.9 years) and specifically for those on active duty (30.4±7.4 years), generally reflected that of the military population as a whole (mean age in 2019 = 28.2).…”

“…3 Among ankle foot-injuries, lateral ankle sprains (LAS) are among the most common. 4 The rate of ankle sprains in military personnel (~35 per 1000 person-years) 4,5 is nearly five times greater than that reported in the civilian population. 6 While several epidemiological studies have assessed the incidence of ankle sprains in military populations, 4,[7][8][9] none have provided treatment fidelity and contextualized morbidity (e.g.…”

“…10 In the same context and applied at a more macro level, greater granularity for contextualizing burden is needed to properly plan medical staffing and resource requirements to mitigate the impact of ankle sprains and optimize recovery following injury. 5 Therefore, the purpose of this study was to characterize and contextualize the burden of ankle sprain injuries in the U.S. Military Health System. A secondary aim was to assess disparities in healthcare utilization and costs stratified by ankle injury type.…”

“…22 Implementation of interdisciplinary teams, including rehabilitation specialists, on the primary care level with operational military units is also warranted to address the varying complexity of ankle injuries, reduce barriers and delay of care, and facilitate a more rapid return to function. 5,22 Health services research is needed to empirically assess the effectiveness of more contemporary health deliv-ery approaches in the military.…”