Understanding Hip Fracture by QCT-Based Finite Element Modeling
Hip fracture has become a common health problem among old people. Understanding hip fracture mechanics is the first step to effectively prevent hip fracture. The objective of this study was to investigate the combined effect of reversed stress/strain patterns in femur (during single-leg stance and sideways fall) and the inhomogeneous material properties of femur bone. We constructed 40 subject-specific femur finite element models from medical quantitative computed tomography and used them to identify high risk regions in the femur induced by the two loading configurations. The obtained results showed that compared to the single-leg stance, in the sideways fall the highest stress and strain occurred at different locations; and the tensile-compressive stress status was also completely reversed. Previous studies have found that a bone has different strength at different anatomic sites, and at the same site it has different compressive and tensile strength. Our study suggested that, in addition to the large magnitude of impact force induced in falling, the abnormal stress/strain patterns produced by the non-habitual loading condition in falling may be another external contributor to hip fracture.