Purpose: To investigate a computer-assisted technique for retrograde insertion of a percutaneous scaphoid screw and compare insertion time, accuracy, and radiation exposure to the traditional technique. We hypothesize that computer-assisted navigation of volar percutaneous scaphoid screw placement would improve accuracy, require less time, and diminish radiation exposure when compared to the traditional technique.
Methods: Ten matched pairs of cadaveric wrists were randomized to computer-assisted versus traditional volar percutaneous scaphoid screw placement. Time of the overall procedure, set-up time, time for ideal guide wire placement, and radiation time were recorded. Number of K-wire attempts was also recorded. Finally, accuracy of planned screw axis and actual screw axis were compared. Student's t-tests and rank sums were used to determine whether the differences in outcome variables between computer-assisted and traditional techniques was significant, with an alpha level of 0.05.
Results: Although the overall time of the 2 procedures and the set-up time were not different between the 2 groups, the time for placement of the K-wire was halved in the computer-assisted percutaneous scaphoid fixation group, and the number of K-wire attempts needed for accurate screw placement approached clinical significance. Although the radiation exposures for the individual components of set-up time and final check time were not different, the radiation exposures for global time of the procedure, K-wire placement, and screw placement were clinically significant.
Conclusions: Computer-assisted navigation of volar percutaneous scaphoid screw placement takes no more time that traditional methods and significantly reduces the amount of radiation exposure to the patient. Although not statistically significant, the technique reduced the number of incorrect passes of the K-wire, requiring a single attempt in 4 of the 5 specimens.