Summary

Tibial remnant preservation (zone I to III) in ACLR is able to significantly reduce tibial tunnel widening. This effect was stronger in the subgroup with longer remnants (zone III). No other significantly beneficial effects of remnant preservation were observed. There was no increase in the complication rate.

Abstract

Background

The potential benefits of preserving tibial remnant during anterior cruciate ligament reconstruction (ACLR) have been substantially discussed, but the effect of the length and the tissue quality of the preserved ACL remnant remains unclear. Additionally, no reliable method for classification of the tibial ACL remnant has not yet been described.

Purpose

Develop a process for intra-operative classification of ACL remnant. Assess the effect on clinical outcomes and complications of preserving ACL remnant in ACLR cases.

Methods

The arthroscopic video recordings of 115 cases were retrospectively analysed to assess the length of tibial ACL remnant. All cases were performed by a single surgeon, between January 2016 and December 2021.The length of the tibial ACL remnant was assessed in a standardized way by 2 different surgeons, and stratified in 5 categories: no remnant (n=8, zone I (>0 to 25%, n=81), zone II (25 to 50%, n=21), zone III (50 to 75%, n=5), and zone IV (75 to 100%, n=0), relative to the posterior cruciate ligament (PCL). All patients went through the same postoperative follow-up protocol, including PROMs (IKDC, Lysholm and Tegner),return-to-sport (RTS) testing, side-to-side laximetry using GNRB® arthrometer (Genourob, Laval, France), and a high resolution MRI at 12 months postoperative. All cases were assess for complications , including cyclops lesions, tunnel widening, and graft failure – with a minimum follow-up of 24 months.

Results

In terms of postoperative functional knee outcomes and complication, there was no significant association between the no remnant group and all critical zones of the remnant preservation groups. Nevertheless, The remnant preservation group (zones I to III) significantly decreased the tibial tunnel widening by approximately two times the tibial tunnel diameter when compared with the no remnant group by % tibial tunnel expansion (zone I vs. no remnant group was 15.99 ± 8.95 vs. 32.2 ± 13.77 (P = 0.002), zone II vs. no remnant group was 16.98 ± 11.28 vs. 32.2 ± 13.77 (P = 0.012), and zone III vs. no remnant group was 12.95 ± 11.79 vs. 32.2 ± 13.77 (P = 0.047).

Conclusion

Tibial remnant preservation (zone I to III) in ACLR is able to significantly reduce tibial tunnel widening. This effect was stronger in the subgroup with longer remnants (zone III). No other significantly beneficial effects of remnant preservation were observed. There was no increase in the complication rate.
Study design: Retrospective study; Level of evidence, 4.