Biomechanical comparison of tendon repair techniques: Bunnell suture leads in mode of failure and minimally invasive configuration in elongation.

Purpose: In this experimental study, the Minimally Invasive Configuration (MIC), the Bunnell, Kessler and modified Bunnell-Kessler techniques for tendon rupture repair were compared in terms of the following biomechanical parameters: maximum load, mode of failure, failure elongation, tension/construct elongation and stiffness (Young's modulus). The scope of comparison involves understanding the properties of each suture technique in hopes of eventually contributing to surgical decision-making. Methods: Thirty-two frozen ovine specimens were obtained, and transverse tenotomy was performed on each. Eight tendons were randomly allocated to each technique. Specimens were tested performing a unidirectional tensile load to failure using a servo-hydraulic testing device. The tendons were also loaded to failure at a rate of 10 mm/s. The total length of the construct was defined as the distance from the two clamps. Stiffness was calculated by determining the slope of the force-displacement curve in the linear region. Total failure was defined as a drop of measured force or rupture of the tendon-suture complex. Results: In the mode of failure, Tukey's post hoc test showed a statistically significant difference between the Bunnell group and the other three groups ( Conclusion: The Bunnell suture performed best in terms of mode of failure, while the MIC suture technique outperformed the rest in terms of tension/construct elongation. Findings show sufficient biomechanical evidence to support the ongoing clinical application of all techniques. Level of Evidence: Level V.