Association of CT-Derived Psoas Muscle Parameters and Trochanteric Subcutaneous Fat Thickness With Intertrochanteric Fracture Stability in Older Adults
İbrahim Halil Dadir, İsmail Duran, Adnan Arslan, Yunus Oklu, Yunus Can Ünal, Ömer Faruk YıldırımBackground
Unstable intertrochanteric femur fractures are associated with increased morbidity and more complex surgical management than stable fractures. Although computed tomography (CT)-derived body composition parameters have been linked to frailty, mortality, and hip fracture risk, their association with fracture stability remains unclear. This study aimed to investigate the relationship between CT-derived psoas muscle measurements, trochanteric subcutaneous fat thickness, and fracture stability in older adults with intertrochanteric fractures.
Methods
This retrospective cohort study included 154 patients aged ≥65 years who underwent surgery for intertrochanteric femur fractures following low-energy same-level falls between January 2021 and January 2024. Fractures were classified as stable (31-A1) or unstable (31-A2/A3) according to the AO/OTA classification. Total psoas muscle cross-sectional area (CSA), psoas muscle attenuation, and trochanteric subcutaneous fat thickness were measured on preoperative CT images. Multivariate logistic regression was performed after adjustment for age, sex, body mass index (BMI), and Charlson Comorbidity Index (CCI).
Results
Seventy-five patients (48.7%) had stable fractures and 79 (51.3%) had unstable fractures. Compared with the stable group, patients with unstable fractures had significantly lower trochanteric subcutaneous fat thickness, total psoas CSA, and psoas muscle attenuation (all p < 0.001). In multivariate analysis, subcutaneous fat thickness (OR=0.888, 95% CI: 0.841–0.937; p< 0.001), total psoas CSA (OR=0.809, 95% CI: 0.701–0.932; p=0.003), and psoas muscle attenuation (OR=0.886, 95% CI: 0.816–0.962; p=0.004) were significantly associated with fracture instability. Age, sex, BMI, and CCI were not significantly associated with fracture instability.
Conclusion
Lower trochanteric subcutaneous fat thickness, reduced total psoas muscle CSA, and lower psoas muscle attenuation were associated with unstable intertrochanteric fracture patterns in older adults. These findings highlight the potential role of trochanteric subcutaneous fat thickness and psoas muscle characteristics in fracture instability.