Relationship of Cortical and Endocortical-Trabecular Bone Structure to Femoral Strength in a Sideways Fall Configuration
Biomechanics and Bone Quality
Osteoporosis - Assessment
Poster Sessions, Presentation Number: SU0032
Session: Poster Session II & Poster Tours
Sunday, September 14, 2014 12:30 PM - 2:30 PM, George R. Brown Convention Center, Discovery Hall-Hall E
* , UNITED STATES, , UNITED KINGDOM, , UNITED KINGDOM, , UNITED STATES
The relative contribution of cortical and trabecular bone to fragility of the femur is unclear. Our goal is to determine the relationship of cortical and endocortical-trabecular bone structure to proximal femur strength during a sideways fall impact in order to improve current understanding of hip fracture etiology. We hypothesize that the relationship is stronger in areas considered ‘at risk’ of high load during simulation of fracture.
We obtained 70 human cadaveric proximal femurs (45 women, 25 men, range 55-98 years), scanned both using DXA and QCT, and mechanically tested the femurs to failure in a sideways fall configuration. Using a previously published method (Treece 2012), we applied a bone mapping technique (Stradwin, wxRegSurf and Surfstat) to identify regions where bone structure in the hip was significantly related to femoral strength. We spatially aligned the bone measurements onto an average femur surface and used statistical parametic mapping to analyse the results. Covariates were sex, age, height, weight and phantom type. The results are presented as percentage variation in cortical bone mass (Fig. 1A) and endocortical-trabecular density (Fig. 1B) per 1000N of failure load.
Femoral strength is predictive of both cortical bone mass and endocortical-trabecular density over large areas of the proximal femur (Fig. 1A & 1B). The increase in cortical bone mass was quite uniform (Fig. 1A), about 10-20% per 1000N of failure load. The range in increase of endocortical-trabecular density was more variable (Fig. 1B), with the strongest effect located at the femoral neck. Interestingly, both bone variables showed strong association with failure load in the regions that have been predictive of hip fractures in clinical case-control studies (marked with *). The strong relationship between endocortical-trabecular density and failure load in the femoral neck (Fig. 1B) is noteworthy because the current clinical standard for fracture prediction is femoral neck aBMD with clinical risk factors. The association between surface derived bone measurements and failure load was strongest in regions considered be ‘at risk’ of hip fracture.
G. Treece, Patent - GB0917524.1: Other. K. Poole, Patent - GB0917524.1: Other.
* Presenting Authors(s):
, UNITED STATES