Parallel Pin Guide in Femoral Neck Fractures: Comparing the Effect of the Guide between Two Surgeons with Different Levels of Experience

Purpose: Proper fixation of femoral neck fractures requires the parallel insertion of cannulated screws. Using a parallel pin guide has been definitively shown to improve the accuracy of pin insertion. However, no studies have addressed whether or not the surgeon's experience has any influence on the benefits of using a parallel pin guide. Methods: The accuracy of parallel pin insertion was investigated in the laboratory to determine if the surgeon's experience has an effect on the usefulness of the guide. The experiment was carried out using a self-designed parallel pin guide, 24 Sawbones femurs and 48 pins. Two surgeons with different levels of experience performed the procedures with and without the parallel guide. After three pins had been inserted, fluorescent images were taken in anteroposterior (AP) and lateral (Lat) views. Then, two observers measured the divergent angles twice, using computers equipped with Agfa PAS systems. The data were analyzed with the Student t test and the Mann-Whitney U test. Results: When the parallel pin guide was not used, the accuracy of parallel insertion of pins was not affected by the surgeon's experience (p=0.088, 0.075). Although the difference was not statistically significant, the attending surgeon inserted the pins with a greater degree of parallelism. In contrast, when the parallel pin guide was used, the resident doctor was significantly more accurate than the attending surgeon (p=0.015, 0.037). Conclusion: Use of a parallel pin guide tended to improve the accuracy of parallel pin insertion in both surgeons. However, the effect of the guide was more obvious in the less experienced resident surgeon.