A Dual-Plane Method Based on Prior Knowledge Fusion for Locating Holes of Intramedullary Nails

WANG Fei; LIU Xingwang; XU Kaiwen

doi:10.3969/j.issn.1672-9722.2025.05.013

Abstract：In the repair of human long bone fracture,the intramedullary nail needs to be inserted into the medullary cavity in order to fix the fracture area.The difficulty is that distal interlocking hole pose will change with the shape of medullary cavity.There-fore,it is difficult to target the distal interlocking hole with the matching aiming instrument.The traditional location method cannot well meet the actual needs of intraoperative locking nails,which is time-consuming,laborious and difficult to locate accurately,and the success rate is only 30%.High precision is required,and the error needs to be controlled within 2 mm.Firstly,two intraop-erative X-ray images are taken at different angles with the C-arm machine,and the deep neural network is used to accurately pre-dict the projection of the hole's axis in the imaging plane.Then,the initial spatial pose of the hole's axis is determined by construct-ing the projection plane and according to the intersection of the two planes.Finally,the nail's contour information is used to iterative-ly correct the axis pose.The experiments are carried out in the simulated and clinical environments.Comparison is drawn between the calculated hole's axis and the actual hole's axis.Results show that the average distance error is 0.82 mm,and the average angle error is 0.75°.The method can meet the actual surgical needs,and improves the efficiency of locating and planning in the distal in-terlocking intramedullary nail surgery.