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Updated: May 24, 2026
Imaging of the Microstructural Failure Mechanism in the Human Hip
Published on: September 29, 2023
Anatomical patterns and injury count associated with attrition in trainees with hip and pelvic bone stress injuries:
Garry F Dredge1, Daniel I Rhon2, Abe R Dummar3
1University of Kentucky, Lexington, Kentucky, USA gdredge@gmail.com.
Insights
Greater bone stress burden and specific hip/pelvic injuries significantly reduce military trainee graduation rates. Understanding these patterns can improve retention strategies for bone stress injuries.
Area of Science:
- Orthopedics
- Military Medicine
- Sports Medicine
Background:
- Hip and pelvic bone stress injuries (BSIs) are a major cause of attrition in US Army Basic Combat Training (BCT).
- The impact of multiple concurrent BSIs on training completion is not well understood.
- Isolated femoral neck injuries are documented, but multifocal injury effects require further study.
Purpose of the Study:
- To evaluate the association between anatomical injury patterns and the number of affected regions with BCT graduation outcomes.
- To determine if the cumulative bone stress burden impacts training completion.
- To identify specific injury locations associated with attrition.
Main Methods:
- Retrospective cohort study of 123,555 trainees (2015-2017).
- Manual review of MRI reports to identify 1407 hip/pelvic BSI cases.
- Multivariable logistic regression adjusted for age and sex to analyze injury patterns and graduation odds.
Main Results:
- BSI cases had significantly lower graduation rates (63.6%) vs. the total cohort (91.4%).
- Increased bone stress burden (3, 4, or ≥5 regions) progressively reduced graduation odds (ORs 0.67, 0.59, 0.58).
- Femoral head (OR=0.56) and femoral neck (OR=0.77) involvement were independently associated with attrition; older trainees had higher graduation odds post-injury.
Conclusions:
- Higher total bone stress burden and femoral head/neck involvement significantly decrease BCT graduation odds.
- Findings can inform risk stratification for military trainees.
- Identifies high-risk multifocal injury patterns for future management strategies to improve retention.
Background/Purpose:
Hip and pelvic bone stress injuries (BSIs) cause significant medical attrition from US Army Basic Combat Training (BCT). While the morbidity of isolated femoral neck injuries is well documented, the impact of 'total bone stress burden' (concurrent multifocal injuries) on training completion remains unclear. This study evaluated the association between anatomical injury patterns, the number of affected regions and BCT graduation outcomes.
Methods:
This retrospective cohort study analysed data from 123 555 trainees for fiscal years 2015 to 2017. MRI reports were manually reviewed to identify 1407 trainees with confirmed hip or pelvic BSIs. Multivariable logistic regression models, adjusted for age and sex, were used to assess the relationship between the cumulative injury count, specific locations and graduation odds.
Results:
BSI cases had significantly lower graduation rates (63.6%) than the total cohort (91.4%). A significant inverse relationship was observed between total bone stress burden and graduation. Compared with single-site injuries, involvement of three (OR=0.67; 95% CI 0.46 to 0.98; p=0.037), four (OR=0.59; 95% CI 0.41 to 0.84; p=0.004), or ≥5 regions (OR=0.58; 95% CI 0.40 to 0.79; p=0.001) progressively reduced graduation odds. Anatomically, involvement of the femoral head (OR=0.56; 95% CI 0.42 to 0.73; p<0.0001) and femoral neck (OR=0.77; 95% CI 0.61 to 0.97; p=0.028) was independently associated with attrition. Paradoxically, while older trainees had a higher injury incidence, they demonstrated significantly higher odds of graduating post-injury than younger recruits.
Conclusions:
Among trainees who underwent hip/pelvic MRI, greater total bone stress burden and specific involvement of the femoral head or neck were associated with significantly lower odds of BCT graduation. These findings may inform future risk stratification and help identify high-risk multifocal injury patterns that could be evaluated in prospective studies of targeted management strategies to improve military trainee retention.
