Biomechanical Evaluation of a Knotless Barbed Suture Repair in a Human Achilles Tendon Rupture Model

Background. Knotless barbed sutures are seeing more common use in wound closures and small tendon repairs. The purpose of this study was to evaluate the strength and resistance to gap formation of these sutures in larger tendons, such as the Achilles, compared with conventional repair. Methods. Six matched pairs of fresh-frozen human cadaver Achilles tendons were transected to simulate a rupture. Six tendons were repaired using a double Bunnell over-the-top technique with Fiberwire, and the matched pairs were repaired using a double Bunnell knotless technique with barbed suture. The tendons were tested to failure and stiffness, peak failure load, percentage elongation, load at initial gap and load at 5-mm gap (clinical failure) were compared. Results. The mean peak failure load for the Fiberwire group (459 N) was significantly higher (P =.029) compared with the barbed suture group (184 N). Percentage elongation at peak load was significantly lower in the barbed suture group (P =.014), as was percentage elongation at initial gapping (P =.007) and percent elongation at 5 mm of gapping (P =.004). Conclusion. While the knotless barbed suture is attractive for its design and resistance to gap formation, low failure loads compared with conventional suture are concerning for large tendon repairs.Levels of Evidence: Therapeutic, Level IV: Bench testing