Comparison of different suture techniques for Achilles tendon repair in rat model using collagen scaffolds.

PURPOSE: Tendon injury is an increasing problem in orthopedic and trauma surgery due to aging of the population and increased activity demands. Many rodent animal models are used in order to evaluate tendon reconstruction. Although tendon reruptures are a well- -known clinical problem, the outcomes of tendon repair in animal models are rarely discussed in the literature. The goal of the present experimental study was to compare the primary fixation stability of three suture techniques for repair of Achilles tendon defects in a rat model using a collagen scaffold. METHODS: Cadaveric left hind limbs of Sprague-Dawley rats were prepared with an Achilles tendon defect of 3 mm and rejoined using a collagen scaffold. Three suture configurations (simple, simple stitch with additional framing suture, and modified Mason-Allen stitch; n = 5 each) underwent tensile testing until complete failure was observed. RESULTS: Under a load of a mean value of 6.6 N, the failure load of simple stitches was the significantly lowest ( p < 0.01). Both, modified Mason-Allen stitches and simple stitches with additional framing suture showed a mean failure load of more than 14 N. Regardless of the suture technique, most of the samples showed failure of tendon due to suture tear-out. The suture material as well as the scaffold remained mostly intact. CONCLUSIONS: Although simple end-to-end suture techniques are common in the literature, stitches with more suture strands should be preferred. Using techniques like an additional framing suture or modified Mason-Allen stitch, maximum failure load can be doubled and the risk of tendon rerupture may be decreased within in vivo testing.