Summary

Novice surgeons may have difficulty finding the exact anatomic tunnel location during MMPRT repair.

Abstract

Background

Medial meniscus posterior root tear(MMPRT) is a common knee injury that can lead to osteoarthritis if not treated properly. Transtibial pull-out MMPRT repair leads to favorable mid-term outcomes despite the presence of residual meniscal extrusion. The anatomical tibial tunnel position is crucial to successful MMPRT repair; however, the accuracy of tibial tunnel positioning during surgery remains a challenge for novice surgeons. The routine anterolateral (AL) or posterior trans-septal (PTS) viewing methods in tibial tunnel positioning have been suggested to improve accuracy. Still, the comparison of the two approaches in novice surgeons remains limited. Thus, the objective of this study is to evaluate the accuracy of the tibial tunnel position according to the viewing method for novice surgeons compared to experienced ones.

Methods

We evaluated a cohort of 98 patients with transtibial MMPRT pullout repairs from January 2017 to June 2022. Finally, 65 patients were enrolled to evaluate the accuracy of tibial tunnel positioning using anterior and PTS viewing methods in novice and senior surgeons. Expert surgeon using AL viewing (EAL) group were 24 knees, novice surgeon using the AL viewing (NAL) group were 18 knees, and novice surgeon using PTS viewing were 23 knees. For the patients with more than 5-degree varus alignment, we performed concomitant medial open wedge high tibial osteotomy (MOWHTO). All the surgeons used the transtibial pull-out technique. We evaluated the VAS pain score, Lysholm score until postoperative 2 years, F/U MRI exam at 12 months, and 2nd look arthroscopic exam at postoperative 18~24 months. Using the postoperative 3D-CT scan, we examined the difference between the tibial tunnel center (Tc) and anatomical center (Ac) of MMPR. We also conducted a subgroup analysis to evaluate whether the Ac-Tc distance of 5 mm affected clinical outcomes.

Results

There was no demographic difference among the three groups. The mean anatomic tibial insertion center was 39.7% ± 2.7% laterally and 80.8% ± 3.1% posteriorly. The accuracy of the tibial tunnel position using the PTS viewing method was significantly better than the AL viewing method in novice surgeons (p < 0.01). The Tc position by the NAL group revealed more medial (35.01% ± 5.7%) and anterior (78.72% ± 4.5%) than that of EAL and NPTS group (p=0.003). At 2-year F/U, the NAL group revealed inferior Lysholm score (73.4 ± 11.2) than EAL (80.8 ± 10.8) and NPTS (81.4 ± 12.0) group (p=0.014)
In subgroup analysis, the more than 5mm of Ac-Tc distance group included 9 of EAL (37.5%), 8 of NAL (44.4%), and 3 of NPTS (13%). The healing rate of MMPRT repair (p=0.042), medial meniscus extrusion (0.039), and K-L grade progression (p=0.045) were significantly better in the less than 5mm Ac-Tc distance group.

Conclusion

This study supported the idea that the PTS viewing method provides better accuracy for novice surgeons when positioning tibial tunnels during MMPRT repair. A medio-anterior mal-positioned tibial tunnel revealed a higher risk of failure than an anatomic position.