Anterior-Inferior Tibiofibular Ligament Suture-Tape Augmentation for Isolated Syndesmotic Injuries

CATEGORY: Sports; Ankle INTRODUCTION/PURPOSE: Aggressive surgical treatment of isolated syndesmotic injuries has recently gained some traction in the media and sports world. New developments in syndesmotic fixation aim to restore native syndesmotic stability and ankle motion with a goal of returning athletes to sport quickly. However, the best surgical technique is debated. Dynamic repair with a suture- button (SB) can provide an accurate reduction of the syndesmotic space but may alter the rotational kinematics of the fibula. Previous studies have suggested that repair or reconstruction of the anterior-inferior tibiofibular ligament (AITFL) may restore the dynamics of the syndesmosis better than other devices. The purpose of this study was to biomechanically compare SB fixation and augmented repair of the AITLF using suture and suture-tape (ST) in isolated syndesmotic injuries. METHODS: Twelve unpaired lower leg specimens underwent biomechanical testing in 6 states: 1) intact, 2) AITFL suture repair alone, 3) AITFL suture repair + ST augmentation, 4) AITFL suture repair + ST augmentation + SB fixation, 5) AITFL suture repair + SB fixation, and 6) complete syndesmotic injury. The testing consisted of subjecting the ankle joint to 6 cycles of 5 Nm internal and external rotation torque under a constant 750 N axial compression load in a dynamic tensile testing machine. A lower level of torque was chosen than in previous studies in order to replicate physiologic motion of everyday activities instead of injury level forces. The spatial relationship between the tibia and fibula and tibia and talus was continuously recorded using a 5-camera motion capture system. RESULTS: AITLF suture repair and suture repair + ST augmentation repair constructs showed no statistically significant change in fibula kinematics during testing compared to the intact state. The suture repair + SB construct showed increased external rotation of the fibula (p<0.001, mean 2.32 degrees) and medial translation (mean 0.72 mm, p= 0.007) or overtightening compared to the intact state. The suture repair + SB + ST augmentation state also showed increased external rotation of the fibula compared to the intact state (p<0.001). Sagittal plane motion of the fibula was not significantly different in the repair states compared to the intact state. None of the repair states restored talus rotation back to the intact state; however, the repairs that utilized suture tape reduced the talus external rotation laxity compared to the complete syndesmotic injury. CONCLUSION: For isolated syndesmotic injuries without significant fibular displacement, augmentation of the AITFL with suture- tape best restored the rotational profile of the fibula and ankle joint. Suture-button constructs had a tendency to over-tighten and externally rotate the fibula when compared to the intact state. Suture-tape AITFL augmentation may be a good surgical option and alternative to suture-button fixation for isolated syndesmotic disruptions. Further clinical trials are needed to determine the role for suture-tape augmentation of the AITLF in syndesmotic injuries.