[Accurate traction of long bone fracture with full-length planning module of orthopedic robot system: experiments in vitro and in vivo].

Objective To evaluate the precision in location and clinical flexibility of the newly designed full-length planning module of orthopedic robot system in treatment of fractures of long bone.Methods Nine plastic tibia models were selected for the image mosaicing.The full length of each tibia model was measured on the constructed panorama and compared with the real model length to record the length deviation and conduct the precision analysis.Fracture of tibia and fibula with shortening and angulation deformity was caused on a cadaver specimen with two lower limbs.Full-length planning was carried out on the entire tibial panorama with the fracture.After the reduction distance was determined quantitatively,automatic close traction procedure was carried out with the tibial reduction frame to analyze the precision and effectiveness of this module.At the same time,the relative length variation between the two bone fragments was monitored utilizing video camera to ensure the safety of the reduction operation.Image mosaieing, surgical planning,and bone traction were performed on a clinical case of tibial fracture to validate the clinical feasibility of the module.Results An entire tibial panorama could be constructed from 7 - 10 C-arm images collected during the operation.1.5 rain was needed for image collection.The average mosaieing and planning time was 3 min.The mosaieing error was less than 1.5 mm.The average time for the traction frame installation and traction operation was 4 rain.Traction resulted in accurate reposition of the fraeture ends meeting the requirement of surgery in both the cadaver specimen and the clinical case.Conclusion The newly designed lull-length planning module of orthopedic robot system is easy to use and provides effective and accurate traction result in long bone fracture therapy.This module can not only achieve the minimally invasive surgery,but also dramatically decrease the radiation damage to the medical staff.