A New Accurate, Simple and Less Radiation Exposure Device for Distal Locking of Femoral Intramedullary Nails

BACKGROUND: Due to the metal elasticity of intramedullary nails (IMs) and irregularities of the long bone marrow cavity and other reasons, one of the greatest challenges for surgeons is to position the distal locking screw. Therefore, a novel laser guiding navigation device was designed for the distal locking of femoral IMs. The purpose of this study was to compare the effectiveness of the novel device and freehand technique for distal locking of IMs in the femoral model. METHODS: The laser guiding navigation device (laser group) and freehand technique (freehand group) were used in the distal locking of the IMs in the femoral model. All operations were performed by surgeons of the same level. The differences between the two groups were compared in terms of operative time, radiation exposure time, first success rate, deviation angle between ideal trajectory and actual trajectory, and learning curve. RESULTS: The distal locking of the IMs in the femoral model was performed 40 times in each group. The results showed that the laser group was better than the freehand group in terms of operative time (345±165 VS 212±105 seconds, t=4.27, P<0.001), radiation exposure time (164±57 VS 41±15 seconds, t=13.15, P<0.001) and first successrate (χ(2)=21.36, P<0.001). Compared with the freehand group, the actual trajectory of the laser group was closer to the ideal trajectory in coronal and horizontal planes. Furthermore, the learning curve time of the laser group was shorter. CONCLUSION: Compared with traditional freehand technique, the novel laser guiding navigation device can shorten the operative time and reduce radiation exposure invitro. In addition, it is easy to master with more accuracy and a higher first success rate in vitro.