Three-dimensional computer-assisted navigation for the placement of cannulated hip screws. A pilot study.

PURPOSE: Medial femoral neck fractures are common, and closed reduction and internal fixation by three cannulated screws is an accepted method for the surgical treatment. Computer navigation for screw placement may reduce fluoroscopy time, the number of guidewire passes and optimise screw placement.

METHODS: In the context of a sawbone study, a computer-assisted planning and navigation system based on 3D-imaging for guidewire placement in the femoral neck was tested to improve screw placement. Three screws were inserted into 12, intact, femoral sawbones using the conventional technique and into 12, intact, femoral sawbones guided by the computer-based navigation system. Guidewire and subsequent screw placement in the femoral neck were evaluated.

RESULTS: Use of the navigation system resulted in a significant reduction of the number of drilling attempts (p≤0.05) and achieved optimised accuracy of implant placement by attaining significantly better screw parallelism (p≤0.05) and significantly enlarged neck-width coverage by the three screws (p≤0.0001). Computer assistance significantly increased the number of fluoroscopic images (p≤0.001) and the operation time (p≤0.0001).

CONCLUSIONS: Three-dimensional computer-assisted navigation improves accuracy of cannulated screw placement in femoral neck while increasing the number of fluoroscopic images and operation time. Additional studies including fractured sawbones and cadaver models with the goal of reducing operation time are indispensable before introduction of this navigation system into clinical practice.