DISTAL LOCKING OF UNSLOTTED FEMORAL NAILS - A COMPARISON BETWEEN A RADIOLUCENT DRILL (RD) AND A MECHANICAL DISTAL AIMING DEVICE (DAD)

Although the free-hand technique remains the most popular method for d istal interlocking screw insertion, proximally mounted ''radiation-ind ependent'' devices which compensate for implant deformation recently h ave been developed for rotationally stiff, unslotted femoral nails. Ho wever, the benefits of such systems have not been determined. This stu dy prospectively compared the duration of the nailing procedure, the l ength of radiation time, and the accuracy of interlocking screw placem ent with a radiation-independent distal aiming system to those using t he free-hand technique. In twenty paired intact cadaveric femora, a si ngle surgeon experienced only in the freehand technique performed stat ically locked intramedullary nailing using the two methods. For the ai ming system and free-hand technique respectively, the total operation time was 19.1 +/- 8.4 versus 20.9 +/- 11.3 minutes (p = 0.9), the dist al locking time was 6.6 +/- 2.4 versus 4.8 +/- 1.5 minutes (p = 0.002) , the total fluoroscopy time was 23 +/- 17 versus 69 +/- 34 seconds (p < 0.0001], and the distal locking fluoroscopy time was 0 versus 37 +/ - 15.5 seconds (p < 0.0001). There were no failures in either group. D rill nail contact (p < 0.0001) and distal screw damage (p = 0.02) were both greater with the free-hand technique.