Inertial measurement unit for radiation-free navigated screw placement in slipped capital femoral epiphysis surgery

Slipped Capital Femoral Epiphysis (SCFE) is a common pathologic hip condition in adolescents. In the standard treatment, a surgeon relies on multiple intra-operative fluoroscopic X-ray images to plan the screw placement and to guide a drill along the intended trajectory. More complex cases could require more images, and thereby, higher radiation dose to both patient and surgeon. We introduce a novel technique using an Inertial Measurement Unit (IMU) for recovering and visualizing the orthopedic tool trajectory in two orthogonal Xray images in real-time. The proposed technique improves screw placement accuracy and reduces the number of required fluoroscopic X-ray images without changing the current workflow. We present results from a phantom study using 20 bones to perform drilling and screw placement tasks. While dramatically reducing the number of required fluoroscopic images from 20 to 4, the results also show improvement in accuracy compared to the manual SCFE approach.