SLR - May 2014 - Emily Quinn
Reference: Viens NA, Wijdicks CA, Campbell KJ, Laprade RF, Clanton TO. Anterior Talofibular Ligament Ruptures, Part 1: Biomechanical Comparison of Augmented Brostrom Repair Techniques with the Intact Anterior Talofibular Ligament. The American Journal of Sport Medicine. 42(2): 405-411, 2014.
Scientific Literature Review
Reviewed By: Emily Quinn, DPM
Residency Program: Grant Medical Center
Podiatric Relevance: Lateral ankle instability is a common presenting complaint in podiatric offices. Eighty-five percent of ankle sprains involve the lateral collateral ligaments. Of these injuries, about one third of the injuries result in chronic instability and recurrent sprain. However, there are multiple ways to fix a chronic lateral ankle instability including primary repair, secondary repair and suture tape augmentation. This study compares the failure loads of the intact Anterior Talofibular Ligament (ATFL), suture tape augmentation, and a standard Brostrom repair with suture tape augmentation.
Methods: This was a cadaveric study involving 18 fresh frozen cadaver ankles randomized into three groups – each group with six specimens. The first group included intact ATFL which was identified through standard technique. All soft tissue was removed from the fibula, talus and calcaneus except for the intact or repaired ATFL. The suture tape augmentation surgical technique, group two, was performed utilizing the 4.75 mm suture anchor and the 2 mm wide suture tape with braided ultra high molecular weight polyethylene and polyester through the standard technique established by Arthrex, Inc. The Brostrom repair with suture tape augmentation, group three, was performed by utilizing two No. 0 Fiberwire for the Brostrom repair and the suture tape augmentation was performed in the same technique as previously described.
All specimens were tested by stabilizing the calcaneus to a foot plate and the subtalar joint was then stabilized with two screw fixation. The fibula was the fixated in place at two levels. The foot was held in 10 degrees of plantar flexion and 20 degrees of inversion – stressing the ATFL. This fixture was then mounted to the load actuator of dynamic tensile testing machine. A video extensometer was then utilized to accurately measure the displacement of the fibula relative to the talus. Tensile forces were then applied to the fibula until load to failure resulting in 3.0 mm of displacement of the fibula was recorded.
Results: The load to failure of the suture tape augmentation alone (315.5 N) was significantly higher than the intact ATFL (154.0 N). The mean ultimate load to failure of the Brostrom repair with suture tape augmentation was not significantly different than the intact ATFL. The load to failure of the two separate techniques was not significantly different from each other. The ATFL failure resulted in avulsion from the talus. The suture tape augmentation resulted in suture pullout of the anchor at the fibula (5/6) and talus (1/6).
Conclusion: This study demonstrates and reinforces multiple other studies that the Brostrom repair of the ATFL is weaker as compared to the intact ATFL. The study suggested that both the suture tape augmentation alone and with the Brostrom resulted in the stronger and stiffer repair as compared to the standard Brostrom repair. This study suggests viable biomechanical information regarding the suture tape augmentation. However, one must keep in mind that increased strength and increased stiffness compared with the intact ATFL does not necessarily translate into superior treatment options for the patient. Additional research is needed in clinical trials and patient outcomes before the suture tape can be recommended for lateral ankle instability treatment options.