Densitometric heterogeneity and unstable intertrochanteric fracture morphology in older adults: a retrospective cohort study

Intertrochanteric femur fracture (ITF) stability influences fixation strategy and early mechanical behavior, yet the relationship between densitometric heterogeneity and adverse fracture morphology remains unclear. This study evaluated whether regional bone mineral density (BMD) parameters and hip–spine T-score discordance were associated with Evans-defined unstable ITF morphology in older adults. This retrospective cohort study included 286 older adults treated with proximal femoral nailing (PFN) for low-energy ITFs. Fractures were classified using the AO/OTA and Evans systems, and patients were divided into Evans-defined stable and unstable groups. Evans-defined stability served as the primary outcome, whereas AO/OTA subtype was used for descriptive morphologic characterization. Lateral wall insufficiency and comminution were also assessed. BMD was measured by dual-energy X-ray absorptiometry during the index hospitalization after surgical stabilization and before discharge at the contralateral femoral neck, total hip, and lumbar spine (L1–L4). Densitometric variables were interpreted as post-fracture in-hospital markers associated with fracture morphology rather than as pre-injury or real-time preoperative predictors. Hip–spine T-score discordance was defined as an absolute difference of at least 1.0 SD between lumbar spine and total hip T-scores and categorized as concordant, hip-worse, or spine-worse. Separate covariate-adjusted logistic regression models were constructed. Femoral neck T-scores were similar between stable and unstable fractures. Lumbar spine T-scores were lower in unstable fractures, whereas total hip T-score was not significantly associated with instability after adjustment. The spine-worse discordance pattern was more frequent in unstable than stable fractures (20.1% vs. 9.2%). In adjusted analyses, each 1-SD decrease in lumbar spine T-score was associated with Evans-defined instability (adjusted OR 1.46, 95% CI 1.15–1.86; p = 0.002), and spine-worse discordance pattern was also associated with unstable fracture morphology (adjusted OR 2.08, 95% CI 1.12–3.84; p = 0.021). Unstable fractures also more commonly showed lateral wall insufficiency and comminution. Hip–spine T-score discordance, particularly a spine-worse pattern, was associated with Evans-defined unstable fracture morphology in older adults with ITFs. Although lateral wall insufficiency and comminution were more common among unstable fractures, their direct associations with discordance patterns were not evaluated. Because DXA was performed after fracture occurrence and surgical treatment, these findings should be interpreted as post-fracture observational associations rather than evidence of preoperative prediction or causality. Not applicable.