Biomechanical Effect of Filled Biomaterials on Distal Thai Femur by Finite Element Analysis

Abstract

Giant cell tumors are frequently detected at the lower end of the distal femur. Surgery is the most effective treatment for these tumors. The experience of the surgeons determines the amount of bone removal containing the giant cell tumors (excision) and what biomaterials should be used for the bone replacement; however, the strength of the reconstructed bone has been a concern. Finite elements analysis was employed in this study to analyze the direction to fill and the appropriate quantity of biomaterial, namely polymethylmethacrylate (PMMA) or hydroxyapatite (HA), which was used to replace the bone. With PMMA replacement, increased quantities of PMMA replacement made the maximum von Mises stress nearly constant. The surgeon should fill the PMMA replacement from the lateral to the medial side to reduce the maximum von Mises stress on PMMA. With HA replacement from the lateral to the medial side, the maximum von Mises stress slightly increased when the biomaterials were added under walking conditions and were nearly stable when added under stair climbing conditions. However, HA replacement from the medial to the lateral side produced the highest maximum von Mises stress when three parts of biomaterial were added under both conditions. The surgeon should fill the HA replacement from the lateral to the medial side to minimize the maximum von Mises stress on the HA. In addition, finite elements analysis seemed to be a useful tool, combined with the surgeons’ experience to validate suitable biomaterial or an appropriate procedure for better results in bone surgery.