Prevention Strategy of Intra-articular Screw Penetration During Internal Fixation of Femoral Neck Fracture

Abstract Objective: This study obtains a specific fluoroscopic view by using geometric methods, which can detect whether there is unrecognized joint penetration (UJP) during the operation. Methods: A retrospective analysis was conducted including 52 patients with femoral neck fractures who underwent internal fixation with cannulated screw at the Department of Orthopedics of the xxx from January 2021 to June 2021. The specific fluoroscopic view that can detect the UJP is obtained by using the geometric method and correction formula. The accuracy and effectiveness of this special fluoroscopic view acquisition method were verified by preparing four femoral models of UJP. Results: There were 21 patients (40.38%) with unrecognized screw penetration, and 5 patients (9.62%) occurred UJP. Among them, 3 patients occurred in the anterosuperior (AS) area (5.77%), 1 patient in the posterosuperior (PS) area, and 1 patient in the posteroinferior (PI) area (1.92%). In the research and verification of special fluoroscopic views, the lateral view was set as 0°, and the specific fluoroscopic view θ= arctan (M 1 O ′/M 2 O ′), if the screw is located in the anteroinferior (AI) and PS regions of the femoral head, it is a - θ °rollunder lateral view; If the screw is located in the area of AS and PI femoral head, it is a θ °rollover lateral view. In the validation experiment, using the above method, the UJP model of the four regions can find screw penetration in the specific fluoroscopic view. Conclusion: In this study, a special fluoroscopy view can detect whether there is screw penetration during internal fixation of femoral neck fracture and effectively reduce the incidence of UJP.