The Risk of Iatrogenic Peroneal Nerve Injury in Lateral Meniscal Repair and Safe Zone to Minimize the Risk Based on Actual Arthroscopic Position: An MRI Study

Abstract

Background: Lateral meniscal repair using an all–inside meniscal repair device involves a risk of iatrogenic peroneal nerve injury. To our knowledge, there have been no previous studies evaluating the risk of injury with the knee in the standard operational figure-of-4 position with joint dilatation in arthroscopic lateral meniscal repair. Purpose: To evaluate and compare the risk of peroneal nerve injury and establish the safe and danger zones in repairing the lateral meniscus through the anteromedial, anterolateral, or transpatellar portal in relation to the medial and lateral borders of the popliteal tendon (PT). Study Design: Descriptive laboratory study. Methods: Using axial magnetic resonance imaging (MRI) studies of knees in the figure-of-4 position with joint fluid dilatation at the level of the lateral meniscus, we drew direct lines to simulate a straight all–inside meniscal repair device deployed from the anteromedial, anterolateral, and transpatellar portals to the medial and lateral borders of the PT. If the line passed through or touched the peroneal nerve, a risk of iatrogenic peroneal nerve injury was noted, and measurements were made to determine the safe and danger zones for peroneal nerve injury in relation to the medial or lateral border of the PT. Results: Axial MRI images of 29 adult patients were reviewed. Repairing the lateral meniscus through the anteromedial portal in relation to the lateral border of the PT and through the anterolateral portal in relation to the medial border of the PT had a 0% risk of peroneal nerve injury. The “safe zone” in relation to the medial border of the PT through the anterolateral portal was between the medial border of the PT and 9.62 ± 4.60 mm medially from the same border. Conclusion: It is safe to repair the body of the lateral meniscus through the anteromedial portal in the area lateral to the lateral border of the PT or through the anterolateral portal in the area medial to the medial border of the PT. Clinical Relevance: There is a risk of iatrogenic peroneal nerve injury during lateral meniscal repair. Thus, we recommend repairing the lateral meniscal tissue through the anteromedial portal in the area lateral to the lateral border of the PT and using the anterolateral portal in the area medial to the medial border of the PT, as neither of these approaches resulted in peroneal nerve injury. Additionally, the surgeon can decrease this risk by repairing the meniscal tissue using the all–inside meniscal device in the safe zone area.

The Risk of Iatrogenic Posterior Neurovascular Injuries in Lateral Meniscal Repair Based on the Standard Arthroscopic Knee Position: A Magnetic Resonance Imaging Study

“…In a study published in 2021, 3 our author group evaluated the risk of posterior neurovascular injuries related to the medial border of the popliteus tendon using preoperative MRIS with the knees in a slightly flexed position and found that there was a risk of injuries when repairing posterior meniscal tissue 19.01 ± 4.67 mm beyond the medial border of the popliteus tendon through the anteromedial portal and 16.53 ± 4.30 mm beyond the medial border of the popliteus tendon through the anterolateral portal. In another study, 2 1 year later, we used MRIS with the knees in the standard arthroscopic position to evaluate the safe and danger zones of repairing lateral meniscal tissue and found that the danger zone was 15.84 ± 4.52 mm beyond the medial border of the popliteus tendon through the anteromedial portal and 9.62 ± 4.60 mm beyond the medial border of the popliteus tendon through the anterolateral portal. However, even though that study 2 evaluated the risk of injuries based on the real-life arthroscopic situation, there was 1 important point of concern: the reference landmark was the medial border of the popliteus tendon, which is quite distant from the posterior meniscus root, leading to a chance of error when applying the results to the actual operative situation.…”

“…In another study, 2 1 year later, we used MRIS with the knees in the standard arthroscopic position to evaluate the safe and danger zones of repairing lateral meniscal tissue and found that the danger zone was 15.84 ± 4.52 mm beyond the medial border of the popliteus tendon through the anteromedial portal and 9.62 ± 4.60 mm beyond the medial border of the popliteus tendon through the anterolateral portal. However, even though that study 2 evaluated the risk of injuries based on the real-life arthroscopic situation, there was 1 important point of concern: the reference landmark was the medial border of the popliteus tendon, which is quite distant from the posterior meniscus root, leading to a chance of error when applying the results to the actual operative situation. To decrease this potential risk in the current study, we used the landmark of the lateral border of the posterior LMR to determine the risk of injuries as well as define the safe and danger zones, which are easier to identify and closer to the posterior lateral meniscal tissue than the landmark of the medial border of the popliteus tendon.…”

“…1,4,5,9,13,14 The main type of injury during this procedure is accidental penetration of a posterior neurovascular structure by the needle tip of an all-inside meniscal repair device, and various studies have identified ''safe'' and ''danger'' zones during the meniscal repair procedure. However, these studies have generally consisted of 2 types, cadaveric 10,11 or magnetic resonance imaging (MRI), 2,3,6 and both types had some notable limitations. All of the cadaveric studies evaluated the risk of iatrogenic posterior neurovascular injuries using midthigh to midleg knee sections, which had no natural tension in soft tissue or neurovascular structures.…”

Assessing Risk of Iatrogenic Peroneal Nerve Injury in All-Inside Lateral Meniscal Repair Between Standard Vs. Arthroscopic MRI

“…Axial oblique MRI scans passing through the center of the lateral meniscal tissue were used for the study measurements, with the medial border of the patella chosen as the position of the anteromedial portal and the lateral border of the patella chosen as the anterolateral portal. The risk of iatrogenic peroneal nerve injury was evaluated by drawing a direct line from the anteromedial or anterolateral portal to the medial or lateral border of the popliteus tendon, extending 14 mm beyond the joint capsule, following the recommendations from earlier studies 9,15,16 . The shortest distance was measured from the direct line to the outer border of the peroneal nerve (Fig.…”

No risk of iatrogenic peroneal nerve injury in all-inside lateral meniscal repair with either 14- or 18-mm needles through the popliteus tendon in the standard arthroscopic knee conditions

“…However, with this technique, there are concerns of potential iatrogenic injury to the peroneal nerve (PN), which is located in close proximity to the lateral joint line in the posterolateral knee compartment [9]. Cadaveric and magnetic resonance imaging (MRI) studies have been conducted to evaluate the risk of injury to the posterolateral neurovascular structures of the knee [1, 4, 7, 8, 12, 14–16, 18, 21, 23, 24, 26]; however, none of these studies focussed on the surgical technique of placing an anchor through the PT or simulated their repairs in knees in the standard arthroscopic lateral meniscal repair position. (see Fig.…”