MRI-Based Assessment of the Common Peroneal Nerve in ACL-Injured Versus Normal Knees: Implications for Inside-Out Lateral Meniscus Repair.

Abstract

Objectives: This study investigates the risk of CPN injury by measuring the nerve's proximity to the trajectory of a straight needle inserted from the anteromedial portal at the knee joint level during inside-out lateral meniscus repairs in both ACL-injured and normal knees.

Methods: In this retrospective study, we examined MRI scans of 30 ACL-injured knees and 30 normal knees. A reference line was drawn 1 cm medial to the patellar tendon at the joint level, extending to the lateral margin of the popliteus and continuing posteriorly. Perpendicular distances from this line to the CPN were measured to compare anatomical variations between the groups. These measurements were analyzed using paired t-tests, with a p-value of less than 0.05, which is considered statistically significant.

Results: Analysis of 60 MRI scans revealed that the CPN is located significantly closer to the reference line in ACL-injured knees (mean distance: 1.59 cm) compared to normal knees (mean distance: 2.01 cm), with a p-value of less than 0.005. This finding suggests a higher potential risk of nerve injury in ACL-injured knees during inside-out meniscal repair procedures.

Conclusion: The CPN is located significantly closer to potential surgical paths in ACL-injured knees compared to normal knees. These findings highlight the importance of meticulous surgical planning and technique adjustments to minimize the risk of CPN injury during inside-out meniscus repairs especially when using straight needles.