AFFIRM-CT and Clinical Study

SNF grant # 183584 with HUG, INS, HES-SO and UK.
Most hip fractures are caused by falls resulting in an impact force that exceeds the femoral bone strength. The AFFIRM-CT project aims to develop a new hip fracture risk model based on the risk of falling and integrating a CT-based femoral bone strength. During the last year, a model to predict a personalized fall rate was developed with the analysis of three different cohorts. Preliminary results showed that the number of prior falls and fear of falling are predictive for future falls. Furthermore, to estimate the energy absorbed by soft tissues during a fall, the soft tissue thickness over the hip was extracted from CT images and compared with the stiffness measured with a soft tissue indentation device at the same location. We previously evaluated the 3D-Shaper software, which proposes to reconstruct a 3D image of the proximal femur from a 2D DXA scan and thus offers an interesting alternative when a QCT scan is not available. We extended our evaluation, which had focussed on shape and density so far, with a comparison of the bone FEA. Since March 2021, we are enrolling participants in a clinical study to validate these models. The assessment includes the risk of falling, the general health state and bone quality with HR-pQCT and DXA measurements.

Average damage derived from QCT based (left) and 3D DXA (right) based FE simulations. 0: undamaged; 1: fully damaged.