Direct Repair of the ACL: Healing Comparison with ACL Reconstruction at MRI Evaluation

Presentation Format: Scientific poster presentation.

Purpose or Learning Objective: Primary anterior cruciate ligament repair (ACLrep) was recently proposed as an alternative to ACL reconstruction (ACLRec) in proximal acute ACL tears. This study compared the healing of a repaired ACL and the healing of a reconstructed ACL as evaluated by 1.5-T magnetic resonance imaging (MRI) at 1-year follow-up.

Methods or Background: A total of 30 patients with proximal ACL tears (Sherman types I and II) underwent primary ACL repair with the transosseous pull-out technique. Thirty patients with type III and IV underwent ACLRec with doubled gracilis and semitendinosus tendons graft. Two criteria were used to evaluate graft incorporation at MRI: signal-to-noise quotient (SNQ) and graft maturity (water content of the graft based on Howell's scale).

Results or Findings: A sample size calculation demonstrated the need for 30 patients in each group for a power of 95% (with a 97.5% confidence interval [CI]). A 1.5-T MRI was used to evaluate graft status and graft integration at 1 year postoperatively using the parameters of SNQ and ligament signal determined using Howell's scale. Radiologic parameters were evaluated by an expert radiologist and an orthopaedic surgeon, and Cronbach's α was used to assess interobserver (0.86) and intraobserver (0.82) reliability. There were no significant differences in sex distribution, age, preoperative Tegner level, and body mass index between groups. The mean SNQ was 2.21 ± 2.45 for ACLrep and 2.52 ± 1.69 for ACLRec (p = 0.266). The unilateral 95% CI for SNQ in ACLrep was 2.21 (to 3.08) (< 4.21 limit for noninferiority) and ACLRec was 2.52 (to 3.12); p = 0.128. Hence nonstatistical differences between the two groups according to the SNQ and noninferiority were proven. For Howell's scale in ACLrep, 21 patients were assigned to grade 1, 7 to grade 2, 2 to grade 3, and 0 to grade 4. In ACLRec, 20 patients were assigned to grade 1, 6 to grade 2, 4 to grade 3, and 0 to grade 4. Howell's scale showed no differences between groups (p = 0.769).

Conclusion One year postoperatively, the MRI appearance of a repaired ACL showed noninferior maturation compared with a reconstructed ACL.

Publication History

Article published online:
03 June 2021