Experimental Study of Distal Interlocking of a Solid Tibial Nail: Radiation-Independent Distal Aiming Device (DAD) Versus Freehand Technique (FHT)

OBJECTIVES:Recently, radiation-independent aiming devices for the tibia that compensate 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 length of radiation time, and the accuracy of interlocking screw placement when using a radiation-independent distal aiming device (DAD) versus the freehand technique (FHT). MATERIALS AND METHODS:In an oblique cadaveric tibial fracture, a surgeon inexperienced in both techniques (DAD and FHT) performed statically locked intramedullary nailing. RESULTS:For the DAD and the FHT, respectively, the total operation time was 25.4 ± 11.3 (mean ± standard deviation) versus 30.9 ± 14.3 minutes (p = 0.029), the distal locking time was 16.7 ± 8.6 versus 21.9 ± 10.5 minutes (p = 0.004), the total fluoroscopy time was 9 ± 5 versus 93 ± 34 seconds (p < 0.0001), the distal locking fluoroscopy time was zero versus 88 ± 33 seconds (p < 0.0001), and the screw wear was −0.7 ± 5.2 versus 26.8 ± 31.6 micrometers (p = 0.001). The failure rate was 1.6 percent (one of sixty screws) in both groups. CONCLUSION:These results suggest that the DAD can eliminate the need for radiation during placement of distal interlocking screws.