High- and low-viscosity cement for osteoporotic femoral augmentation: A computational subject-specific approach

Abstract

The risk of osteoporotic hip fractures may be reduced by augmenting susceptible femora with high- and low-viscosity cement. As the injection of excessive amounts of cement may result in thermal necrosis of bone tissue or even embolism, the minimum cement volume required to achieve a predefined level of augmentation should be determined. To this end, the present work introduces a novel efficient generalized augmentation strategy combining a strain-based fracture criterion with experimental results of bone augmentation previously obtained. The proposed methodology aims to estimate the fracture load improvement with two cement types (high- or low-viscosity).In total, 18 healthy and 17 osteoporotic ex vivo femora were numerically studied using the Finite Element Method and considering a typical lateral fall on the greater trochanter. In all cases, both a nonaugmented and an augmented state with injected bone cement were simulated. All augmented models of femora exhibited enhanced fracture loads regardless of the cement viscosity used. Low viscosity cement showed a higher fracture load improvement than high-viscosity cement. Furthermore, augmentation of osteoporotic femora estimated a larger improvement in the fracture load (10.32 ± 3.22% with high-viscosity cement and 28.93 ± 7.04% with low-viscosity cement) with respect to healthy femora (9.41 ± 3.66% with high-viscosity cement and 25.19 ± 6.00% with low-viscosity cement). The results suggest that low-viscosity cement can be a powerful candidate for use in femoroplasty. Furthemore, the proposed methodology can be efficiently used for preoperative planning of bone augmentation surgery.