Analysis Of MRI-diagnosed Femoral Neck Bone Stress Injuries And Graduation Outcomes In Army Trainees

PURPOSE: Bone stress injuries, particularly at the femoral neck, lead to significant long-term health burdens, while also imposing substantial financial costs and operational challenges on the Army. This study assessed the association between MRI-diagnosed femoral neck bone stress injuries (FNBSIs) and Basic Combat Training (BCT) graduation outcomes. Specifically, we examined whether FNBSI characteristics—such as grade, laterality, and anatomical location — affect graduation rates. Additionally, this study evaluated consistency of radiologists in reporting FNBSI grade and specific anatomical location. METHODS: This retrospective case-control study included 208,540 trainees from four BCT sites between 2015 and 2019. MRI data, including injury location, and presence of bone marrow edema, were extracted from 6,697 imaging studies, with approximately 26.1% (n = 1,750) showing positive FNBSI cases across 1,464 trainees. Cases were classified based on radiology reports using the Fredericson MRI grading system (Grades 1-4). Graduation outcomes were compared between cases (n = 1,464) and sex- and age-matched controls (n = 4,392). Logistic regression analyses and chi-square tests were conducted to assess the impact of FNBSI characteristics on graduation status. RESULTS: Trainees with FNBSIs showed a 57.9% graduation rate, markedly lower than controls at 90.4% (OR = 7.06, 95% CI: 6.097-8.166, p < 0.0001). Bilateral FNBSIs were associated with lower graduation rates (55.0%) compared to unilateral injuries (61.5%; OR = 1.31, 95% CI: 1.06-1.61, p = 0.0126). Tensile-side fractures were associated with a lower graduation rate compared to compressive-side fractures; however, the difference was not statistically significant (OR = 1.64, 95% CI: 0.67-4.04, p = 0.2832). Higher-grade injuries (Grade 3 or 4) were linked to poorer graduation outcomes, with Grade 4 injuries associated with the lowest rate (50.7%). Radiologists specified the grade in only 40.1% of MRIs, with 70.5% of cases lacking a specific anatomical location. CONCLUSION: FNBSIs adversely affect trainee success, with bilateral and higher-grade injuries contributing to lower graduation rates. This study highlights the need for consistent radiological reporting to improve diagnostic accuracy and outcomes tracking in the future.