Computer-assisted fracture reduction: a new approach for repositioning femoral fractures and planning reduction paths

Reduction is a crucial step in the surgical treatment of bone fractures to achieve anatomical alignment and facilitate healing. Surgical planning for treatment of simple femoral fractures requires suitable gentle reduction paths. A plan with optimal movement of fracture fragments from the initial to the desired target position should improve the reduction procedure. A virtual environment which repositions the fracture fragments automatically and provides the ability to plan reduction paths was developed and tested.

Virtual 3D osseous fragments are created from CT scans. Based on the computed surface curvatures, strongly curved edges are selected and fracture lines are generated. After assignment of matching points, the lines are compared and the desired target position is calculated. Planning of reduction paths was achieved using a reference-coordinate-system for the computation of reduction parameters. The fracture is reduced by changing the reduction parameters step by step until the target position is reached. To test this system, nine different fractured SYNBONE models and one human fracture were reduced, based on CT scans with varying resolution.

The highest mean translational error is 1.2 ± 0.9 (mm), and the rotational error is 2.6 ± 2.8 (°), both of which are considered as clinically acceptable. The reduction paths can be planned manually or semi-automatically for each fracture.

Automated fracture reduction was achieved using a system based on preoperative CT scans. The automated system provides a clinically feasible basis for planning optimal reduction paths that may be augmented by further computer- or robot-assisted applications.