Analysis on circumpelvic muscle force and spatial position and orientation of bone traction needle for pelvic fracture reduction

Abstract

Robot-assisted reduction of pelvic fracture, the bone traction needles need to be inserted into the iliac bone of the affected pelvis, and the clamping instrument of the robot is connected to the bone traction needle. The biomechanical characteristics of the pelvic musculoskeletal tissues are different with the different spatial position and orientation of the bone traction needle. In this paper, a new PA-MTM model considering the pinnate angle of skeletal muscle is proposed to analyze the muscle force of skeletal muscle. According to the planned reduction path, reduction force during the reduction process is calculated. Based on the pelvic CT scan data and the muscle distribution of the pelvis, the musculoskeletal model of the fractured pelvis is reconstructed. Then, the finite element model of the pelvic musculoskeletal tissue with bone traction needle is established. The maximum reduction force is applied on the bone traction needles, and the stress distribution of the pelvic musculoskeletal tissue with the needles in different spatial position and orientation is comparatively studied. The results show that the suitable force point on bone traction needle is S1 point. When the bone traction needle is inserted into the iliac crest and the anterior inferior iliac spine, the pelvis is in a good stress state.