Summary

Remnant Preservation in ACL reconstruction, keeps biology and doesn’t compromise with tibial tunnel positioning

Abstract

Introduction

Remnant preservation during anterior cruciate ligament (ACL) reconstruction is controversial. The technique may confer several advantages, but it is unclear whether the remnant helps or hinders the positioning of the tibial tunnel. OBJECTIVE: The purpose of this study was to compare the positioning of the tibial tunnel between the technique of remnant preservation with the non-preserving technique. The hypothesis is that the use of the perforation technique totally within the ACL remnant does not compromise the positioning of the tibial tunnel, determined by postoperative three-dimensional computed tomography (3D-CT). STUDY DESIGN: Prospective cohort study; Level of evidence, 3. METHODS: Between October 2018 and December 2019, patients undergoing ACL reconstruction underwent surgery with a remnant preserving technique (Group 1) if they had ACL remnant present (>50% native ACL length), or underwent removal and cleaning of ACL remains and use of standard landmarks for positioning the tibial tunnel (Group 2 - control). After the procedure, the tunnel location was evaluated by 3D-CT. Measurements were performed in relation to the distance from the center of the tibial tunnel to the medial border and the anterior border of the tibia in relation to the greatest anteroposterior (AP) and mediolateral (ML) distance of the total tibial dimensions visualized on 3D-CT and expressed in percentages, and the tunnels were classified as anatomical or non-anatomical. Specifically, if the center of the tibial tunnel was between 30% to 55% anterior to posterior, and 40% to 51% medial to lateral, it was classified as anatomical positioning. RESULTS: 52 patients were included in the study (26 in each group). The mean tunnel positions were 36.8 5% AP and 46.7 2.9% ML in group 1, and in group 2 they were 35.6 4.8% AP and 47.3 2.3% ML. There were no significant differences in the mean AP (p=0.134) and ML (p=0.098) tunnel positions between the groups. Inter- and intra-observer reliability ranged from moderate to excellent, and good to excellent, respectively. There was no significant difference in the rate of malpositioning between the groups (group 1, 7.7%; group 2, 11.5%; p=1,000). CONCLUSION: Perforation entirely within the tibial remnant of the ACL using a ligament remnant preservation technique showed no difference in relation to the positioning of the tibial tunnel determined by postoperative 3D-CT, when compared to total removal of the ACL remnant and use of references pattern.