ISAKOS: 2023 Congress in Boston, MA USA

2023 ISAKOS Biennial Congress ePoster

 

Comparing the Risk of Iatrogenic Peroneal Nerve Injury in All-inside Lateral Meniscus Repair between Preoperative and Real Arthroscopic Position MRIs

Chaiwat Chuaychoosakoon, MD, Hat Yai, Songkhla THAILAND
Wachiraphan Parinyakhup, MD, Hadyai, Songkhla THAILAND
Tanarat Boonriong, Principal, Hat Yai, Songkla THAILAND

Prince of Songkla University, Hat Yai, Songkhla, THAILAND

FDA Status Not Applicable

Summary

It is safe to perform an operation using the safe and danger zones identified on preoperative MRIs; the major difference from making assessments based on actual arthroscopic position MRIs is that there will be fewer and smaller safety zones.

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Abstract

Background

Repairing lateral meniscal tissue with an all-inside meniscal repair device can endanger the peroneal nerve. Several studies have evaluated the risk of such injuries using preoperative magnetic resonance imaging (MRI) with the knee in the slightly flexed position, but there is a major concern involving the reliability of such studies. The actual lateral meniscal repair is performed in the arthroscopic figure-of-4 position with joint fluid dilatation, in which the anatomical relationship of the peroneal nerve and the posterior neurovascular structure of the knee can be quite different from the preoperative MRI position. To our knowledge, there have been no previous studies confirming that the preoperative MRI has sufficient accuracy to determine the actual intraoperative risk of iatrogenic peroneal nerve injury in this procedure.

Purpose

To evaluate and compare the risk of peroneal nerve (PN) injury in all-inside meniscal repair of the lateral meniscus through the anteromedial and anterolateral portals in relation to the medial and lateral borders of the popliteus tendon (PT) using MRIs of the two knee positions in the same patients.

Methods

This was a prospective comparative study. Using axial MRI studies of knees in the slightly flexed knee position and the figure-of-4 position with joint fluid dilatation at the level of the lateral meniscus, direct lines were drawn simulating a straight all-inside meniscal repair device deployed from the anteromedial and anterolateral portals to the medial and lateral borders of the PT extending 14 mm past the joint capsule. The closest distance was measured from each direct line to the PN. If a line passed through or touched the PN, a risk of iatrogenic injury was noted and a new direct line was drawn from the same portal to a border of the PN. The danger zone was measured from the first line to the new direct line along the joint capsule. The statistical significance of the deemed risks of injury between the two knee positions for all measurements were assessed using the Chi-square and Wilcoxon signed-rank tests, with p-value < 0.05 considered to indicate statistical significance.

Results

Preoperative and actual arthroscopic position axial MRI images of the knees of 28 adult patients were reviewed. The assessed risks of iatrogenic peroneal nerve injury in simulated all-inside meniscal repair using preoperative MRI images were non-statistically significantly higher than when using actual arthroscopic position MRI images except for simulated repairs through the anterolateral portal in relation to the lateral border of the popliteus tendon (p-value = 0.04). Of interest, we saw that all danger zones assessed in the post-operative MRIs were included within the danger zones as assessed by the preoperative MRI images.

Conclusion

Preoperative MRIs do not accurately determine the actual intraoperative risk of iatrogenic peroneal nerve injury in this procedure, but we found that all of the risks of iatrogenic peroneal nerve injury and danger zones assessed using the actual arthroscopic position MRI images were included within the risks and danger zones identified using the preoperative MRI images.