Assessment of Local Bone Mineral Density With Strain-Gage Instrumented Surgical Tools

The bone mineral density (BMD) in a given fracture site may affect the outcome of fracture fixation. Low BMD values, such as those occurring in osteoporotic bone, can determine the fixation method and the postoperative care. Evaluation of the BMD is either done subjectively during surgery or by a preoperative measurement. The technique most commonly used to measure BMD preoperatively is dual-energy X-ray absorptiometry (DEXA). DEXA scans have been shown to be site specific [1,2] and therefore may be inaccurate in determining local BMD at the fixation site. Furthermore, in trauma cases, patients frequently do not present with a pre-operative DEXA scan; and the ideal method of assessment would be intraoperative. Intraoperative BMD assessment could be used to guide surgical decisions such as the point of entry of a screw for a fracture plating system or use of locking versus non-locking screw-plate contruct.