Computer navigation allows for accurate reduction of femoral fractures

Femoral nailing for reduction and stabilization of femoral fractures is a common orthopaedic procedure. However, angular and rotational malalignment is not an infrequent result, and extensive use of fluoroscopy is commonly involved. We tested the accuracy of a computerized navigation system to enhance multiplanar fracture reduction and to decrease the requirement for fluoroscopy. We used a cadaveric femur fixed in a simulator and optically tracked. After obtaining five fluoroscopic images for each reduction attempt, accuracy measurements were taken. We first measured alignment of the intact bone using the navigation system, followed by open and blind reduction of simple and segmental fractures. For the blind, closed reduction trials, the accuracy of restoration of femoral length was 1.2 +/- 0.4 mm (mean +/- standard deviation) for a simple fracture and 1.9 +/- 1.8 mm for a segmental fracture. Rotational accuracy was 1.7 degrees +/- 1.9 degrees and 2.5 degrees +/- 1.8 degrees, respectively. Open reduction using this model yielded no difference between the reduced fracture and the intact bone in coronal and rotational alignment. Computerized navigation has the potential for increasing precision in fracture reduction while minimizing fluoroscopic requirements.