Development of intraoperative noninvasive force measuring system during femoral fracture reduction

Fracture reduction is a critical step in minimally invasive surgery of displaced femoral fracture treatment. Skeletal traction and alignment for fracture reduction can be performed individually in the operation, which is a standard procedure for the surgeons in practice. The intraoperative counteracting soft tissue forces during the fracture reduction should be measured precisely for improvement of the operation. In this paper, a set of measurement system was developed to obtain the value of the forces. Forces of skeletal traction and alignment were measured by three individual sensors, and the corresponding results can be recorded instantaneously during the fracture reduction process. According to an experimental test, the maximum alignment force in X-axis and Y-axis direction were 48.4N and 240.1N, respectively. The maximum traction force was 379.7N, occurred because of the slight valgus positioning of the leg to be convenient to insert the intramedullary nail. The highest forces were mostly observed along the shaft axis for skeletal traction. The experimental results show the effectiveness of the proposed measurement system, and indicate the potential application in developing new instruments for the fracture reduction operation.