Risk of Iatrogenic Peroneal Nerve Injury in Inside-Out Lateral Meniscal Repairs Using Differently Curved Repair Devices and Surgical Portals.

Inside-out meniscal repair is a widely adopted treatment for lateral meniscal injuries. A significant complication associated with this procedure is iatrogenic peroneal nerve (PN) injury, reported in approximately 9% of cases. The risk varies depending on the choice of surgical portals, curvature of repair devices, and anatomical landmarks. This study aimed to assess the risk of PN injury and define safe zones for inside-out lateral meniscal repair using different device curvatures and portal combinations. Axial MRI scans of knees positioned in the figure-of-four posture, with joint fluid distension and varus force applied, were analyzed in 29 adult patients. Transparent overlays representing the operative routes of the anterior-, middle-, and posterior-curved needles were superimposed on the MRI scans. Simulations of repair procedures were performed using the anteromedial, accessory anteromedial, anterolateral, and accessory anterolateral portals, targeting the medial and lateral borders of the popliteus tendon (PT). Instances where the needle path intersected or contacted the PN were recorded to delineate risk zones. Repairs targeting the medial PT border with anterior-curved devices via the anteromedial or accessory anteromedial portals were identified as safe. At the lateral PT border, all device curvatures and portals were considered safe, except for middle- and posterior-curved devices used through the accessory anteromedial portal, which posed a risk of PN injury. The risk of iatrogenic PN injury in inside-out lateral meniscal repair depends on the curvature of the repair device and portal used. Adhering to the identified safe zones can substantially reduce this risk.