InternalBrace for Anatomic AITFL Augmentation and Syndesmotic Stabilization: Results at Long-term Follow Up

Abstract

Category: Ankle; Trauma Introduction/Purpose: In the light of recent randomized control trials, both suture-button and syndesmotic screw fixation are considered standard-of-care for syndesmotic fixation, but no gold standard currently exists. An alternative technique that has been described to stabilize the syndesmosis is with use of suture-tape (InternalBrace, Arthrex) to augment a torn AITFL. This method has been the subject of several biomechanical studies that show it better restores anatomic relationships and can provide a preinjury level of syndesmotic stability. Additionally, it is thought to allow for protected healing of native ligaments, which may be of benefit to patients in the long-term. With this study we sought to explore the long-term outcomes of anatomic augmentation of the AITFL with the InternalBrace for the treatment of syndesmotic injury. Methods: We identified 31 patients who had suffered an acute or subacute syndesmotic injury and were treated with the InternalBrace technique (with or without adjunctive syndesmotic fixation) over a 12-month period from 2019-2020 by a single surgeon. The primary outcome variable was the Olerud-Molander Ankle Score (OMAS) at long-term follow up (12-36 months). Other outcomes collected were FAOS scores, range of motion data, and complications. Additionally, radiographs at five timepoints were reviewed to determine maintenance of syndesmotic reduction. Results: At final follow-up, 15 patients completed the primary outcome with a mean OMAS of 78 (SD, 18). All 31 patients were determined to have a successful syndesmotic reduction at the time of the index procedure. No patients were noted to have a radiographic loss of reduction with a tibiofibular clear space > 6mm at time of final radiographic follow up (mean follow-up 439 days). For those patients with ROM data collected at final follow up, 12/15 patients were limited in dorsiflexion (average deficit 6 degrees), and 7/15 in plantarflexion (average deficit 14 degrees). In total, 10/31 patients developed symptoms of anterolateral impingement, for which six underwent secondary arthroscopic debridement. Conclusion: We report the first mid-to-long term clinical results of a newer alternative method of syndesmotic stabilization. Functional results are comparable to current standards-of-care. AITFL augmentation provides consistent anatomic reduction of the syndesmosis with enough biomechanical strength to resist rotation and diastasis. However, in some patients the development of irregular thickening/scarring of the AITFL contributed to symptoms of anterolateral impingement and stiffness. To avoid this complication, alterations in technique, such as a more proximal application of the suture-tape or avoidance of overtightening, are possible and emphasize the importance of future research.