Factors associated with intracapsular versus extracapsular hip fracture patterns in elderly patients following low-energy falls: a retrospective analysis from a single tertiary-care center in China

Abstract

Background Hip fractures represent a significant clinical and public health challenge in the elderly, particularly as populations age globally. While low-energy falls are the primary mechanism of injury, the specific risk factors differentiating intra-capsular and extra-capsular hip fractures remain inadequately characterized. Existing research has largely focused on general fracture risks, leaving a gap in understanding how geometric, nutritional, and metabolic parameters distinctly influence fracture type. Elucidating these differences is essential for advancing personalized prevention in vulnerable aging populations. Objectives This study aimed to identify and compare risk factors associated with intra-capsular and extra-capsular hip fractures among elderly patients following low-energy falls. Methods A retrospective analysis was conducted involving 636 patients aged 70 years or older with hip fractures. Demographic characteristics, geometric parameters (including neck-shaft angle, cortical index, and Singh index), and biochemical markers (hemoglobin, albumin, total protein, and fasting blood glucose) were evaluated. Multivariable logistic regression was employed to identify predictors of fracture type. Results Patients with extra-capsular fractures were significantly older and exhibited lower hemoglobin levels, albumin, total protein, cortical index, and neck-shaft angles, along with higher fasting blood glucose compared to those with intra-capsular fractures (all p < 0.05). The logistic regression model identified cortical index, neck-shaft angle, hemoglobin, and fasting blood glucose as significant independent predictors of fracture type. Conclusion Extra-capsular hip fractures are associated with poorer nutritional status, reduced bone density, smaller neck-shaft angle, and higher blood glucose levels. These findings suggest that extra-capsular fractures are differentially associated with poorer nutritional status, reduced cortical thickness, smaller neck-shaft angles, and higher glucose levels. Our results provide preliminary evidence that combined assessments may aid in risk stratification; however, these associations warrant confirmation in prospective cohort studies before clinical translation.