Summary

Femoral tunnel position has an impact on post-operative meniscal tear risk after ACL-R and an anatomic femoral tunnel position has protective effect on post-operative survival of menisci.

Abstract

Background

Surgical technique accounts for 30-50% of failed ACL reconstruction (ACL-R) procedures, with femoral tunnel malposition being responsible for the majority of cases. A paucity of data still exists, however, regarding whether femoral tunnel positioning contributes to subsequent meniscal tears after ACL-R.

Purpose

The objective of this study was to determine if a relationship exists between the position of femoral tunnel in ACL-R and subsequent meniscus tears.
Study Design: Case-control study

Methods

An IRB-approved chart review was performed using patients who had undergone ACL-R between 2010 and 2019 at one institution. From this cohort, patients were separated into two matched groups of 85 patients each (N=170). Group 1 consisted of patients with symptomatic, meniscus tears post ACL-R requiring treatment. Group 2 consisted of patients without any known, postoperative, symptomatic tears. Average follow up for both groups was >25 months. For both groups, femoral tunnel positions were measured by 3 authors using the quadrant method, which generates two ratios; one related to the sagittal diameter of the lateral femoral condyle (a/t), and the other related to the intercondylar notch height (b/h) to determine anatomic placement of femoral tunnel position of ACL-R. A Wilcoxon sign-ranks paired test was used to compare measurements between the groups. Statistical significance was set at p<0.05.

Results

Group 1 (symptomatic, operative meniscus tears post ACL-R) included 60 patients (71%) with a meniscus tear concurrent with ACL injury. Of these 60 patients, 53 (83%) underwent concurrent meniscus repair at the time of index ACL-R, and 7 (12%) did not undergo meniscus repair at the time of index ACL-R. Group 2 (no symptomatic, operative meniscus tears post ACL-R) included 76 patients (89%) with a preoperative meniscus tear. Of these 76 patients, 70 (92%) underwent concurrent meniscus repair at the time of index ACL reconstruction, and 6 (8%) did not undergo meniscus repair at the time of index ACL-R. For Group 1, average femoral tunnel ratio a/t was 32.1% (± 11.0), statistically significant less anatomic than group 2, 29.0% (± 7.0; p<0.01).

Conclusions

There is higher risk of subsequent meniscus tears when ACL-R is not done according to anatomic principles. In addition, the findings of this study reiterate the importance of femoral tunnel position in ACL graft placement, not only to preserve the reconstructed ACL, but also to decrease the risk of subsequent meniscus tears and help prevent further cartilage injury in patients.