Background: Musculoskeletal injuries plague the Military Health System, affect return to duty, and are a primary source of disability in the US Military. This problem translates into over 25 million limited-duty days and over 900,000 Service members affected each year. The cumulative incidence of injuries requiring an outpatient visit in US Army entry-level training is about 25% for men and 55% for women. Low back pain and lower extremity injuries account for over 44% of limited duty days annually. In addition, Service members who sustain a prior musculoskeletal injury are at increased risk for future injuries.
Objective/Hypothesis: The objective and overall hypothesis is that Service member performance on a battery of physical performance tests performed upon discharge from physical rehabilitation will be able to predict (1) the risk of sustaining any injury as well as (2) the risk of reoccurrence of the same injury. A two-pronged injury prevention approach is required to optimize return-to-duty rates after injury: screening for known preventable musculoskeletal risk factors and ensuring these risk factors are mitigated prior to discharge from rehabilitation. The current assumption is that a Service member discharged from medical care is ready to return to full duty. Because history of prior injury is a well-established risk factor, every Service member that is discharged from physical rehabilitation is already at a higher risk for future injury. Identifying those at increased risk of recurrence provides the ability for secondary and tertiary prevention programs to optimize return-to-duty rates.
Hypothesis 1: Risk factors shown to be predictive of lower extremity and lumbar/thoracic spine injuries in other populations and in healthy Service members will also be predictive of re-occurrence of original injury, future injury, and return-to-duty rates in Service members being discharged from physical rehabilitation.
Hypothesis 2: The injury prediction models will vary by age and sex.
Hypothesis 3: A multi-factorial prediction model that accurately predicts risk of new and recurring injuries, as well as return-to-duty rates, will consist of multiple variables.
(1) To improve prediction of injury-free return to duty following physical rehabilitation, we will compare and contrast select physical performance test results in Service members that sustain an injury or reoccurrence of previous injury versus those that do not during the 12-month follow-up period.
(2) Develop predictive models from collected variables in order to derive a multi-factorial injury risk prediction algorithm to identify high-risk Soldiers in the return-to-duty process.
(3) Develop an optimal physical performance standard that should be met prior to discharge from physical rehabilitation with the aim of decreasing future injury risk and facilitating successful injury-free return to duty.
Study Design: Prospective cohort study.
Relevance: There is no standard physical performance measure for ensuring appropriate, safe, and rapid return to full duty following physical rehabilitation. Because both prior injury and decreased performance on physical performance measures are powerful risk factors for future injury, this may be an important and overlooked approach to help improve effective management of current musculoskeletal injuries, prevent future injuries, and improve injury-free return-to-duty rates. The goal of this study is to develop clear criteria to assess and meet following physical rehabilitation from a musculoskeletal or thoracic injury to promote an injury-free return to duty.