Arthroscopic Quantification of Syndesmotic Instability in a Cadaveric Model

Purpose To investigate whether arthroscopy or stress radiography can identify instability resulting from single-ligament injury of the ankle syndesmosis and to determine whether either modality is capable of differentiating between various levels of ligament injury. Methods Syndesmotic/deltoid ligament sectioning was performed in 10 cadaver legs. Arthroscopic evaluation and fluoroscopic stress testing were completed after each sectioning. In group 1 (n = 5), sectioning began with anteroinferior tibiofibular ligament (AITFL), then interosseous membrane (IOM), posteroinferior tibiofibular ligament (PITFL), and deltoid. In group 2 (n = 5), this order was reversed. Measurements were made by determining the largest-sized probe that would fit in the anterior and posterior syndesmosis. Radiographic parameters included tibiofibular overlap/clear space and medial clear space. Results No radiographic measurement proved useful in distinguishing between intact and transected AITFL. Anterior probe (AP) size reached significance when distinguishing between intact and AITFL-transected specimens ( P < .0001). AP detected significant differences comparing single with 2-, 3-, and 4-ligament (AITFL, IOM, PITFL, deltoid) disruptions ( P = .05,