Purpose: Current methods of anterior talofibular ligament (ATFL) reconstruction fail to restore the stability of the native ATFL. Therefore, augmented anatomic ATFL reconstruction gained popularity in patients with attenuated tissue and additional stress on the lateral ankle ligament complex. The aim of the present study was to evaluate the biomechanical stability of the InternalBrace (Arthrex Inc., Naples, FL, USA), a tape augmentation designed to augment the traditional Broström procedure.
Methods: Twelve (12) fresh-frozen human anatomic lower leg specimens were randomized into two groups: a native ATFL (ATFL) and a tape augmentation group (IB). Dual-energy X-ray absorptiometry (DEXA) scans were carried out to determine bone mineral density (BMD) of the specimens. The ligaments were stressed by internally rotating the tibia against the inverted fixated hindfoot. Torque at failure (Nm) and angle at failure (°) were recorded.
Results: The ATFL group failed at an angle of 33 ± 10°. In the IB group, construct failure occurred at an angle of 46 ± 16°. Failure torque reached 8.3 ± 4.5 Nm in the ATFL group, whereas the IB group achieved 11.2 ± 7.1 Nm. There was no correlation between angle at ATFL or IB construct failure or torque at failure, respectively, and BMD for both groups.
Conclusion: This study reveals that tape augmentation for ATFL reconstruction shows similar biomechanical stability compared to an intact native ATFL in terms of torque at failure and angle at failure. BMD did not influence the construct stability. Tape augmentation proved an enhanced initial stability in ATFL reconstruction which may allow for an accelerated rehabilitation process.
Level of evidence: II.
Keywords: Anterior talofibular ligament reconstruction; Biomechanical stability; Bone mineral density; Lateral ankle instability; Tape augmentation.