Burden of Musculoskeletal Injuries in U.S. Active Duty Service Members: A 12-Year Study Spanning Fiscal Years 2010-2021.

Background: Musculoskeletal injuries (MSKIs) represent the most substantial and enduring threat to U.S. military readiness. Previous studies have focused on narrow surveillance periods, single branches of service, and used variable approaches for MSKI identification and classification. Therefore, the goals of this retrospective population study were to report the incidence, prevalence, and types of MSKIs sustained by active duty service members (ADSMs) across four Services in direct care (DC) and private sector care (PC) settings over fiscal years (FYs) 2010-2021, and to quantify and describe associated health care utilization and PC costs over the same period.

Methods: This study included ADSMs from the Air Force, Army, Marine Corps, and Navy. Prevalence and incidence rates for Head/Neck, Upper Extremity (UE), Spine (upper back, middle back, lower back, pelvic), and Lower Extremity (LE) MSKIs in ADSMs, associated health care utilization, and PC costs were derived by querying electronic health records from DC, PC claims, and theater medical data from the Military Health System Data Repository. Patient episodes of care and associated PC costs related to MSKIs in DC and PC settings were classified into mutually exclusive outpatient encounter categories and acute inpatient stays, body regions, and Services.

Results: Over FY10-21, the most prevalent MSKIs were LE (24-29%) followed by Spine (17-20%), UE (14-16%), and Head/Neck (6-8%). Across FY10-21, soldiers were more likely to sustain LE MSKI than Airmen (risk ratio 1.12-1.30) and Marines demonstrated an increasing risk of LE MSKI prevalence and incidence (relative to Airmen) over the study period. The rise in prevalence of LE, Spine, UE, and Head/Neck MSKIs over FY10-21 was accompanied by increased health care utilization and reliance on PC care, especially same-day surgeries (SDS). PC reliance for SDS increased across body regions from FY10 to its peak in FY20 (Head/Neck: 22.7% to 49.7%, Spine: 37.1% to 57.0%, LE: 38.6% to 51.5%, UE: 40.4% to 53.5%). In FY21, the MHS incurred the highest PC costs for LE MSKIs ($132,242,289), followed by Spine ($98,738,863), UE ($92,118,071), and Head/Neck ($42,718,754).

Conclusions: To our knowledge, this is the first population study of MSKIs in ADSMs spanning the ICD-10 CM transition (FY15-16) that includes the four Services. Across Services, MSKIs in the U.S. military remain a prevalent and persistent problem. Consistent with prior research, the LE was the most common and costly body region affected by MSKIs. Service members with MSKIs demonstrated an increasing reliance on PC for MSKI care, particularly SDS, over the study period. Expanding future research efforts to include all Services to assess risk factors and patient outcomes for treatments across DC and PC settings is vital to mitigate the threat posed by MSKIs to the readiness of the U.S. Armed Forces.