Evaluation of a synthetic bone defect test model to aid in the selection of materials for use in vertebral body compression fracture repair

A synthetic test model was developed to assist in screening injectable cements with a focus on mechanical strength for vertebral body compression fracture repair. The two-part defect model consisted of a polyurethane foam cube to simulate trabecular bone and a defect to which various injectable cements could be introduced. In addition, a finite element analysis model was developed and the results were compared to laboratory testing. Agreement was found between the finite element analysis and test results. Once the finite element analysis model was validated with experimental data, an additional finite element analysis was conducted to study various parameters affecting mechanical performance such as simulated bone and cement stiffness. Finite element analysis models were also created using orthotropic bone properties typical of healthy trabecular bone and were compared to various foam stiffnesses. The foam model was a good in vitro representation of actual trabecular bone found in vertebral bodies and is a valid model to evaluate the mechanical strength of injectable cements for percutaneous vertebral body fracture repair