Syndesmotic Fixation With Suture Button. Neurovascular Structures at Risk. A Cadaver Study

Abstract

Category: Trauma Introduction/Purpose: Damage to distal tibiofibular syndesmosis occurs in 25% of operative ankle fractures. Syndesmotic stabilization is crucial to prevent significant pain, instability and degeneration of the joint. One operative method is insertion of suture buttons. Though effective, this method can result in entrapment and damage of the saphenous neurovasculature of the medial tibia. The purpose of this study was to describe the anatomic risk of direct injury to the saphenous nerve and greater saphenous vein during syndesmotic suture button fixation. Methods: This study was performed on 10 below knee cadaveric leg specimens. Under fluoroscopic guidance, syndesmotic suture buttons were placed from lateral to medial at 1cm, 2cm, and 3cm above the tibial plafond at an anterior angle of 30 degrees to the coronal plane. Dissection was performed through medial tibial incision to record the distance and position of each button from the greater saphenous vein and saphenous nerve. Statistical measurement and analysis was performed with SPSS. Results: The mean age of cadavers was 78.2 ± 6.9 years and mean BMI was 21.6 ± 2.2. The mean distance of the saphenous nerve to the suture buttons at 1cm, 2cm, and 3cm were 7.1 ± 5.6mm, 6.5 ± 4.6mm, and 6.1 ± 4.2mm, respectively. The saphenous nerve was compressed in 2 cadavers (20%) at 1cm, 2 cadavers (20%) at 2cm and 1 cadaver (10%) at 3cm by suture buttons. Mean distance of the greater saphenous vein from the suture buttons at 1cm, 2cm and 3cm were 8.6 ± 7.1, 9.1 ± 5.3, and 7.9 ± 4.9mm respectively. The great saphenous vein was compressed in 2 cadavers (20%) at 1cm, 1 cadaver (10%) at 2cm and 1 cadaver (10%) at 3cm by suture buttons. Conclusion: There was at least one case of injury to both the saphenous vein and nerve at every level of button insertion at a rate of 10-20%. The close proximity of the suture button to neurovasculature combined with significant anatomic variation in saphenous nerve anatomy suggest that neurovascular injury may be best avoided by direct visualization prior to suture button placement. Great care should be taken to avoid injury to saphenous neurovascular structures during suture button insertion. Keeping an eye on close proximity of neurovasculatures, we recommend medial incision for during syndesmotic suture button fixation.