Internal Fixation of Femoral Neck Fractures with Computer Assisted Surgery

This paper describes procedures for repositioning calculations of fractured bone fragments using 3-D-computed tomography (CT), aimed at preoperative planning for computer-guided fracture reduction of the proximal femur. Fracture boundaries of the bone fragments, as "fracture lines (FLs)," and the mirror-transformed contralateral femur shape extracted from 3-D-CT were used for repositioning of the fragments. We first describe a method for extracting FLs based on 3-D curvature analysis and then formulate repositioning methods based on registration of bone fragments using the following three constraints: 1) contralateral (CL) femur shape; 2) FLs; and 3) both CL femur shape and fracture lines, as "both constraints". We performed experiments using CT datasets from five simulated and four real patients with proximal femoral fracture. We evaluated the rotation error in reposition calculations and the contact ratio between repositioned fragment boundaries, which are crucial for the recovery of proper functional axes and bone adhesion of fragments, respectively. Experimental results showed that good accuracy and stability were attainable when registration using both constraints was performed after registration using the fracture-line constraint. On average, 6.0 degrees +/-0.8 degrees in rotation error and 89%+/-3 % in contact ratio were obtained without providing precise initial values.

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Implementation of a new navigated parallel drill guide for femoral neck fractures

Kendoff

Hüfner

Citak

et al. 2006

Computer Aided Surgery

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Trauma navigation modules often use conventional mechanical surgical tools for basic simulation of drilling procedures or single screw placement. However, the precise parallel placement or specific angles that may be required are not displayed on the navigation screen. A more complex mechanical tool, a parallel drill guide (PDG) for femoral neck fractures, was integrated into a navigation module as part of this study, thus combining the advantages of mechanical tools with the benefits of fluoroscopic navigation. To implement a conventional PDG with a conventional navigation system, the tool was equipped with a non-detachable reflective marker array. Navigation engineers adapted the software to enable the navigated PDG to be displayed. We evaluated the conventional technique in comparison with the navigated technique using plastic bone models and a fresh frozen cadaver. Implementation of the navigated PDG did not pose any problems, in terms of either the software or the surgical procedure itself. The total operation time was extended by 30%, but the radiation time for the navigated group was reduced by 50%. No software or hardware-related failures occurred. Complete integration of a cannulated parallel drill guide into a navigation system has been successfully implemented. Continuous display of the mechanical guide with two parallel trajectories on the navigation screen enables safe, efficient screw placement within mechanical guidelines, without the need for additional radiographic control once initial registration has been completed.

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Internal Fixation of Femoral Neck Fractures with Computer Assisted Surgery

Cited by 3 publications

References 8 publications

Haptic Rendering of Drilling into Femur Bone with Graded Stiffness

Haptic Rendering of Drilling into Femur Bone with Graded Stiffness

Computer-Assisted Preoperative Planning for Reduction of Proximal Femoral Fracture Using 3-D-CT Data

Implementation of a new navigated parallel drill guide for femoral neck fractures

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