Defining the danger zone for peroneal nerve safety in all-inside lateral meniscus repair: an MRI-based study.

Abstract

Background: The peroneal (fibular) nerve (PN) traverses the posterolateral aspect of the knee joint, placing it at risk during lateral meniscus (LM) repair, given its proximity to the popliteus tendon (PoT).

Objective: This study aimed to evaluate the risk of PN injury and define a safe anchor penetration angle during all-inside LM repair.

Materials and methods: A retrospective analysis was conducted using magnetic resonance imaging (MRI) scans of 327 individuals aged 18-60 years. The patellar tendon (PaT) and PoT widths were measured. The PN location relative to the PoT was determined. Distances from the PN to predefined medial and lateral reference lines across the PoT were calculated. The angular relationship between these lines and the transverse axis of the PaT was also analyzed for both anteromedial (AM) and anterolateral (AL) arthroscopic portals.

Results: The PN-to-PoT distance was found to be comparable for both portals. However, the PN was significantly farther from the lateral reference line in the AM portal and from the medial reference line in the AL portal. The safe upper limit for anchor insertion was approximately 65° from the AM portal and 88° from the AL portal.

Conclusion: Appropriate portal selection and anchor angle during all-inside LM repair can significantly reduce the risk of PN injury. The AL portal offers a broader safe insertion range and may therefore improve nerve protection.