Lower-Extremity Injury Increases Risk of First-Time Low Back Pain in the US Army

Area of Science:

• Military medicine
• Orthopedics
• Epidemiology

Background:

• Low back pain (LBP) and lower-extremity injuries (LEI) are significant causes of disability and lost duty days in military personnel.
• Understanding the relationship between LEI and LBP is crucial for effective injury prevention and rehabilitation strategies in this population.

Purpose of the Study:

• To investigate acute lower-extremity injuries (LEI) as a risk factor for developing low back pain (LBP) in U.S. Army soldiers.
• To compare the time to incident LBP between soldiers with and without a history of LEI.

Main Methods:

• Retrospective cohort study utilizing U.S. Army medical and personnel data from 2007-2011.
• Andersen-Gill Cox regression and accelerated failure time (AFT) models were employed to analyze the risk and timing of LBP after LEI.
• Adjusted hazard ratios (HR) and time ratios (TR) were calculated to quantify the association between LEI and LBP.

Main Results:

• Soldiers with a history of LEI had a 1.7 times higher hazard of developing LBP compared to those without LEI (HR, 1.70).
• LEI was associated with a 10% decrease in mean survival time to LBP onset (TR, 0.901).
• The study included an average of over 213,000 soldiers annually, with 8.44% developing LBP and 11.54% having prior LEI each year.

Conclusions:

• Lower-extremity injuries represent a significant risk factor for the subsequent development of low back pain in military personnel.
• The findings highlight an increased short-term risk of LBP following LEI, emphasizing the need to incorporate this into rehabilitation planning.
• This suggests LEI may be a second-order effect contributing to LBP development, requiring consideration in clinical practice and injury management protocols.