Summary

Proximal tears of the ACL offer the possibility of direct repair, with the benefit of maintaining native tissue and anatomy. There has been a recent resurgence in this approach using modern surgical techniques and technology. Existing literature is promising but relatively limited.

Abstract

Background

Tears of the anterior cruciate ligament (ACL) offer the possibility of direct repair, with the benefit of maintaining native tissue and anatomy. There has been a recent resurgence in this approach in select patients with Sherman Type I and II proximal tears (Sherman et al, 1991) using modern surgical techniques and technology. Existing literature is promising but relatively limited (Achtnich et al, 2016; Murray et al, 2020).

Aim

To report the patient-reported outcome measures (PROMs), clinician-measured outcomes and MRI signal noise quotient (SNQ) (Oshima et al, 2020) of a primary ACL repair cohort and compare this with a matched cohort of ACL reconstructions by the same surgeon.

Methods

A post-hoc analysis was performed on prospectively collected data from 20 consecutive patients who underwent primary ACL repair by the senior author from 2017 to 2020. This was compared to an age and sex-matched cohort of ACL reconstruction by the same surgeon, using PROMs, objective return to sport (RTS) testing, and MRI analysis.

Results

ACL repairs demonstrated equivalent post-operative PROMs to reconstructions as measured by IKDC subjective score (78.5 ± 17.1 versus 83.7 ± 13.3, p = 0.333), Tegner Activity Scale (5.9 ± 1.8 versus 6.1 ± 2.6, p = 0.646) and Lysholm score (89.8 ± 10.0 versus 89.6 ± 10.4, p = 0.762).

RTS assessment of repairs was conducted earlier than reconstructions (8.2 ± 2.8 months versus 10.6 ± 1.4 months, p = 0.020). There was no difference between groups in proportion passing quadriceps strength criteria (50% repairs versus 53% reconstructions, p = 0.097), hop testing and Y-balance testing. There was a significant difference in proportion passing hamstrings strength criteria (86% repairs passed versus 60% reconstructions, p = 0.023) and hamstrings to quadriceps ratio (71% repairs versus 20% reconstructions, p = 0.003).

There was no difference between repair and reconstruction cohorts for post-op stability as measured with side-side laxity on KT-1000 (1.8mm ± 1.4mm versus 1.5mm ± 2.0mm, p = 0.905) or GNRB (1.6mm ± 1.8mm versus 1.5mm ± 2.0mm, p = 0.850).

Differences were seen on 12-month MRI analysis with repairs showing higher SNQ at both femoral (8.8 ± 5.7 versus 4.6 ± 2.9, p = 0.009) and tibial sites (10.0 ± 5.7 versus 4.3 ± 4.2, p = 0.001), with no difference seen at the mid-substance between the groups (12.3 ± 8.5 versus 7.6 ± 5.2, p = 0.074). Repairs demonstrated higher values on average (10.0 ± 5.7 versus 4.3 ± 4.2, p = 0.001). There were no graft failures on MRI in either group.

Conclusions

When patient selection is optimised for Sherman Type I or II tears, ACL repairs demonstrate equivalent patient-reported outcomes and better objective outcomes (hamstrings strength) to reconstructions at an earlier time point post-surgery. Tissue quality as assessed on MRI shows higher signal at tibial and femoral attachment sites.