COMPARISON OF A SCANNER-FREE MECHANICAL T ARGET SYSTEM AND A FREE-HAND TECHNIQUE FOR THE PLACEMENT OF DISTAL INTERLOCKING SCREWS OF TIBIA NAILS

Recently, radiation-independent aiming devices for the tibia which com pensate for insertion-related implant deformation have been developed, but the benefits of such systems have not been determined. This study prospectively evaluated the duration of the nailing procedure, the le ngth of radiation time, and the accuracy of interlocking screw placeme nt with a radiation-independent distal aiming system and the free-hand technique. In an oblique cadaveric tibial fracture, a surgeon inexper ienced with either technique performed a statically locked intramedull ary nailing. For the aiming system and free-hand technique respectivel y the total operation time was 25.4 +/- 11.3 vs 30.9 +/- 14.3 min (P = 0.029), the distal locking time was 16.7 +/- 8.6 vs 21.9 +/- 10.5 min (P = 0.004), the total fluoroscopy time was 9 +/- 5 vs 93 +/- 34 s (P < 0.0001), the distal locking fluorscopy time was 0 versus 88 +/- 33 s (P < 0.0001), and the screw destruction was -0.7 +/- 5.2 vs 26.8 +/- 31.6 mu m (P = 0.001). The failure rate was 1.6% (1 of 60 screws) in both groups. These results suggest that aiming devices can eliminate t he need for radiation during distal interlocking screw placement.