Bone Abstracts

Introduction: Femoral neck fractures and trochanteric fractures are two major types of hip fractures. The BMD changing or hip strength analysis (HSA) of the two type fractures may be different. No research had focused on a large sample of Asian people. This study investigated the differences in BMD and morphologic features of the two type hip fractures of elderly Asian people from QCT.

Methods: A total of 279 elderly Chinese patients with hip fractures due to low-energy fall were included (mean age, 74 years old; femoral neck fracture, n=235; trochanteric fracture, n=144). Each patient underwent QCT scan within 48 h after fracture. The femoral neck region was divided into four quadrants: inferior–anterior (IA), superior–anterior (SA), superior–posterior (SP), and inferior–posterior (IP). Cortical thickness, cortical mass fraction, cortical BMD and trabecular BMD measurement were made at each quadrant. With HSA, measurements of the mineralized bone surface cross-sectional area, the cross-sectional moment of inertia, the section modulus (Z), the buckling ratio were obtained. Linear regression equation was applied to correct coefficients as age, sex and BMI.

Results: Patients with trochanteric fractures showed higher cortical thickness, cortical mass fraction, and cortical BMD at SA quadrant than patients with femoral neck fractures (P<0.01; P=0.01; P<0.01). But, patients with trochanteric fractures had lower trabecular BMD at the SP, IP and IA quadrants (P=0.02; P<0.01; P=0.03). And, no significant differences were found in the parameters of HSA between the two groups.

Conclusions: Severer trabecular osteoporosis is seen in patients with trochanteric fractures than in patients with femoral neck fractures. However, the patients with trochanteric fractures had shown higher cortical thickness, cortical BMD, and cortical mass fraction at femoral neck superior-anterior quadrant, which may be more important to predict hip fracture type.