Discussion
blood loss, fracture-healing
BLOOD LOSS
This study evaluated the efficacy and safety of the laser-guiding navigation system in femoral neck-cannulated screw fixation. Based on Desargues’s projective geometry theorem, the target channel was visualized and located by the intercross laser line using special matching positioning ring. In the in-vitro experiments, we verified the advantages of the device based on the guide pins’ insertion and radiation-exposure time by comparison with the freehand group (Fig. In the in-vivo study, there was no statistical difference in VAS score, fracture-healing time, and Harris score between the laser and freehand groups. The laser group performed better in terms of operative time, radiation-exposure time, and operative blood loss, which can improve the efficiency of surgery (Fig. 
The box plot showed that the laser group was better than the FH group in terms of operation time and radiation exposure time, in-vitro experimentsThrough clinical the in-vivo study, the first success rate of the laser group could reach 93.3% vs. 60% in the freehand group, indicating a significant improvement. We further verified the characteristics of its high accuracy (Fig. 
The box plot showed that the laser group was better than the FH group in terms of operation time and radiation exposure time and blood loss, in-vivo experimentsOver the last decade, the field of orthopedic navigation has developed rapidly. New technologies have been invented to optimize the femoral neck-cannulated screw-inserted procedure. From the first generation, represented by instrument-positioning device [Summary of published technologies of femoral neck cannulated screw insert procedure (2000–2021)ENS Imactis® CTnavigationAmong them, the key characteristics [Although the findings of this study are persuasive, there were limitations. First, the device could achieve precise location; however how to maintain the stability of guide needle in the process of drilling on non-vertical surface must be further improved. Second, the experience level of the two surgeons was comparable; it was impossible to exclude the bias caused by the difference in technical expertise. Third, although the number of cases had reached the sample size required by statistics, more cases in multiple centers would make the results more convincing.