[Impact of tibial tunnel position in artificial posterior cruciate ligament reconstruction on postoperative knee function and stability]

To investigate the impact of tibial tunnel position on postoperative knee function and stability in patients undergoing artificial posterior cruciate ligament (PCL) reconstruction.

A retrospective analysis was conducted on patients who underwent single knee artificial PCL reconstruction between January 2018 and September 2024 and met the inclusion criteria. Based on postoperative three-dimensional (3D)-CT measurements of the tibial tunnel position, the patients were allocated into a low tunnel group ( n=35) and a high tunnel group ( n=30). Except for gender, there was no significant difference between groups ( P>0.05) in age, body mass index, injury side, time from injury to operation, preoperative posterior drawer test grade, knee range of motion (ROM), Tegner score, Lysholm score, International Knee Documentation Committee (IKDC) score, or the composition ratio of combined meniscus and cartilage injuries. The tibial tunnel positions were compared. Postoperative recovery of knee function was evaluated using the IKDC score, Lysholm score, Tegner score, and knee ROM. The differences between pre- and post-operative values (change values) for these indicators were calculated and compared between groups. Posterior knee stability was assessed using the posterior drawer test and the side-to-side difference (SSD) in tibial posterior translation measured on stress radiographs. Patient satisfaction was evaluated using the visual analogue scale (VAS) score. Postoperative complications such as graft failure were recorded.

The relative proximal-distal position of the tibial tunnel was significantly lower in the low tunnel group than in the high tunnel group ( P<0.05), while no significant difference was found in the relative medial-lateral position between groups ( P>0.05). All operations were successfully completed, and incisions healed by first intention. All patients were followed up 12-86 months, with a median follow-up of 23.0 months. The low tunnel group demonstrated superior posterior stability compared to the high tunnel group, showing a significantly lower SSD and lower posterior drawer test grade at last follow-up ( P<0.05). At last follow-up, the change value in the Tegner score and the VAS score for patient satisfaction were significantly higher in the low tunnel group than in the high tunnel group ( P<0.05). No significant difference was found between groups in the change values for IKDC score, Lysholm score, or knee ROM ( P>0.05). Two patients in the high tunnel group underwent revision surgery due to graft failure, whereas no such adverse events occurred in the low tunnel group. The difference in the incidence of complications between groups was not significant ( P>0.05).

Compared with a high tibial tunnel, the low tibial tunnel technique can effectively reduce the graft's turning angle at the proximal tibia and lower the risk of graft failure, thereby significantly improving posterior knee stability and function recovery after artificial PCL reconstruction.