The distal margin of the lateral malleolus visible under ankle arthroscopy (articular tip) from the anteromedial portal, is separate from the ATFL attachment site of the fibula: A cadaver study.

Abstract

The purpose of this study was to evaluate the relationship between the lateral malleolus view under ankle arthroscopy and the anterior talofibular ligament (ATFL) attachment site. Seven normal ankles from Thiel-embalmed cadavers were investigated. Ankle arthroscopy was performed using a 2.7mm-diameter, 30-degree, oblique-viewing endoscope. An antero-medial portal (AM), a medial midline portal (MML), and an antero-central portal (AC) were created in order, and the ankle arthroscope was inserted. The lateral malleolus was visualized as distally as possible, and the site that appeared to be the distal margin was marked with a 1.5mm-diameter K-wire. Visualization with arthroscopy was carried out from all portals to mark the distal margin, and the ankle was subsequently exposed to directly measure the distance from the center of the ATFL attachment site at the fibula to each marking. The distances from the ATFL attachment site to the markings made under arthroscopy from the AM, MML, and AC portals were 10.4±2.6mm, 7.4±1.9mm, and 7.3±1.9mm, respectively. Compared to markings made from the MML or AC portal, the marking made from the AM portal was significantly further away from the ATFL attachment site. A typical ankle arthroscopy portal may not allow complete visualization of the tip of the lateral malleolus, indicating that it may not be feasible to thoroughly observe the ATFL attachment site. It is necessary to perform arthroscopic surgeries with the understanding that the distal margin of the lateral malleolus that appears under ankle arthroscopy is 7-10mm proximal to the ATFL attachment site.