Lower Bone Mineral Density is Associated with Intertrochanteric Hip Fracture.

Background: A better understanding of how bone mineral density and vitamin D levels are associated with femoral neck and intertrochanteric hip fractures may help inform healthcare providers. We asked: 1) In patients age ≥ 55 years, is there a difference in quantitative ultrasound of the heel (QUS) t-score between patients with fractures of the femoral neck and those with fractures of the intertrochanteric region, accounting for other factors 2) In patients age ≥ 55 years, is there a difference in vitamin D level between those with fractures of the femoral neck and those with fractures of the intertrochanteric region, accounting for other factors? 3) Is there an association between vitamin D level and QUS t-score?

Methods: In this retrospective cohort study, 1,030 patients were identified using CPT codes for fixation of hip fractures between December 2010 and September 2013. Patients ≥ 55 years of age who underwent operative management for a hip fracture following a fall from standing height were included. Three orthopaedic surgeons categorized fracture type using patient radiographs. Upon hospital admission, QUS t-scores and vitamin D levels were determined. Descriptive statistics, bivariate analyses and multivariable regression were performed.

Results: Accounting for potential confounders, patients with lower QUS t-scores were more likely to have intertrochanteric femur fractures than femoral neck fractures. In a bivariate analysis, there was no association between vitamin D level and either fracture type. There was no association between vitamin D level and bone mineral density.

Conclusion: Patients with lower bone density that fracture their hips are more likely to fracture in the intertrochanteric region than the femoral neck, but vitamin D levels are unrelated. Awareness of this association emphasizes the importance of bone mineral density screening to assist with intertrochanteric hip fracture prevention.

Level of evidence: III.