Abstract
Introduction
Atypical femoral fracture focused on relation of bisphosphonate use, frequently. However, the mechanism of atypical femoral fracture was not yet clarified. Atypical femoral fractures have been kept femoral shaft cortical thickness and BMD, practically. We hypothesized that atypical femoral fractures were associated with impaired bone quality and curvature of femoral shaft.
Materials & Methods
We experienced four atypical femoral fractures. One was subtrochanteric and three were shaft fracture. Two cases received bisphosphonate therapy for 3–5 years. BMD, bone metabolic markers, and bone quality markers were evaluated. Histomorphometry and collagen cross-link analysis were performed. Curvature of femoral shaft and 3-D finite element analysis in one incomplete fracture case were assessed.
Results
BMD values were either maintained or not severely decreased. Deterioration of bone quality were verified by the results of histomorphometry, collagen cross-link analysis, and bone quality maker. Especially, homocystine values, such as one of bone quality markers, were increased in all cases. All atypical femoral shaft fractures showed outward curvature of femoral bone. In one case of incomplete atypical femoral shaft fracture, stress was concentrated at the fracture region according 3-D finite element analysis.
Conclusions
The results of this study suggest that atypical femoral fractures were estimated associated with deterioration of bone quality and curvature of femoral shaft.
