Locking Stitch Techniques Demonstrate Improved Biomechanical Performance in Cadaveric Midsubstance Achilles Tendon Repair.

BACKGROUND

Surgical repair of the Achilles tendon (AT) requires high failure load while limiting elongation. Midsubstance repairs are particularly reliant on suture techniques and typically use either a whip stitch or a locking stitch, such as the Krackow. Enhancements to the Krackow, such as the gift box, epitendinous, or alternative locking stitch techniques, aim to simplify surgical processes and improve biomechanics. The purpose of this study was to evaluate biomechanical properties of 3 enhanced techniques for midsubstance AT repair. We hypothesized that locking stitch constructs would demonstrate improved biomechanical performance compared with nonlocking constructs by minimizing elongation and increasing failure load.

METHODS

A total of 30 cadaveric lower leg specimens with simulated midsubstance AT ruptures were divided into 3 repair groups: whip stitch with gift box (WG), locking whip stitch with gift box (LG), Krackow stitch with epitendinous baseball (KB) stitch. Samples were preconditioned and then loaded from 20 to 100 N for 1000 cycles, followed by load to failure. Elongation, stiffness, failure load, survival, failure mode, and suture weight (burden) were compared.

RESULTS

KB had the significantly lowest cyclic elongation, whereas LG had the significantly highest failure load. LG failure load increase was achieved while using less suture material than KB. All samples survived the cyclic loading protocol, and all whip stitch groups failed from tissue pull-through, whereas LG and KB failed only 40% from pull-through.

CONCLUSION

This study presents 2 stitch techniques that can improve AT repair failure load (LG) and limit elongation (KB). Locking stitch techniques LG and KB demonstrated a significant improvement in biomechanical performance compared with nonlocking WG. Inferences should be limited to the 3 tested constructs rather than individual technical variables in isolation.

CLINICAL RELEVANCE: The locking whip stitch gift box and Krackow epitendinous baseball stitch techniques are both viable methods for Achilles tendon repair. Nonlocking whip stitch gift box does not provide sufficient fixation.