Comparison of free-hand fluoroscopic guidance and electromagnetic navigation in distal locking of femoral intramedullary nails

BACKGROUND: Although the method has been used widely, one of the greatest challenges for intramedullary nailing is to position the distal locking screw. A new technology, the electromagnetic navigation system, is a radiation-free way to locate the position of the drill bit and provide 3-dimensional real-time feedback of location and orientation of the drill bit relative to the locking holes. The purpose of our study was to evaluate the reliability and efficiency of the free-hand technique compared to the new electromagnetic navigation system. METHODS: Fifty-four patients with femoral fracture who needed treatment with intramedullary nails were divided into 2 groups. One group including 26 patients underwent distal locking using the standard free-hand method, whereas the electromagnetic navigation system was used with the other 29 patients. Intraoperative fluoroscopy exposure times, screw insertion times, and healing times were recorded; these parameters were used for comparison between the 2 groups. RESULTS: There were 17 males and 9 females who had femoral intramedullary nails using the free-hand technique, whereas 21 males and 8 females received intramedullary nails using the electromagnetic navigation system. The mean time of distal locking was 19.5 ± 6.0 minutes in the free-hand (FH) group, whereas the time was 6.1 ± 1.4 minutes in the electromagnetic (ET) group. The exposure time for the FH group was 26.8 ± 13.3 seconds and 2.2 ± 1.1 seconds for the ET group. Healing time proved to be comparable in the FH and ET groups (16.4 ± 3.7 weeks vs 15.1 ± 2.8 weeks). CONCLUSION: Under the premise of achieving the same effect, the electromagnetic navigation system has the advantage of less distal locking time and less radiation dose.