Evolution of Graft Maturation and Tunnel Widening During the First Year Following All-Inside Graft-Link ACL Reconstruction: A Serial MRI Study

 

Purpose or Learning Objective: The all-inside graft-link anterior cruciate ligament (ACL) reconstruction technique uses a semitendinosus graft fixed with loop suspensory devices on the femoral and tibial sides. This technique may have possible benefits but may also have potential problems.

Methods or Background: We prospectively evaluated graft maturation and incorporation and tunnel widening in a group of 20 patients using sequential 1.5-T magnetic resonance imaging (MRI) at 3, 6, and 12 months postoperatively. Inclusion criteria were age 16 to 50 years, chronic ACL tear I, a healthy contralateral side, and no prior injures to the affected knee. The following parameters were considered at each follow-up: signal-to-noise quotient (SNQ), bone–graft integration scale (signal intensity at the bone–graft interface), ligament signal by Howell's scale, and tibial tunnel widening. The final clinical evaluation was performed at a minimum follow-up of 2 years and included physical examination, patient-reported outcomes, and KT-1000 arthrometer. The Mann-Whitney U test was used to analyze differences in imaging findings between different time points.

Results or Findings: The mean SNQ was 4.4 ± 2.6 at 3 months postoperative, 1.6 ± 0.7 at 6 months postoperative, and 1.9 ± 1.4 at 12 months postoperative. A statistical difference was found between 3 and 6 months (p = 0.028) and between 3 and 12 months (p = 0.05) with no differences between 6 and 12 months. The mean tibial tunnel widening was 41.2% ± 36.7% at 3 months, 52.4% ± 18.7% at 6 months, and 45.5% ± 46.6% at 12 months. Tunnel widening reduced significantly at 12 months postoperatively when compared with 6 months postoperatively (p = 0.5). Howell's scale showed statistical significance between 3 and 12 months, with patients identified as grade 1 progressing from 30% to 70% (p = 0.05). The bone–graft integration scale showed statistically significance between 3 and 12 months, with patients identified as grade 1 progressing from 45% to 65%, comparing 3 and 12 months (p = 0.01)

Conclusion: Significant maturation and incorporation of all-inside graft-link ACL grafts occurs by 6 months postoperatively. These promising results suggest that even if cyclic displacement occurs, it does not compromise maturation and incorporation. MRI evidence of graft healing occurred within the tibial socket by 12 months postoperatively with no tunnel enlargement.

Publication History

Article published online:
03 June 2021

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