Comparison of Suture Types and Techniques in Achilles Tendon Repair: An Ex Vivo Biomechanical Animal Experiment

The ideal suture technique and type in tendon repair remain unclear. This biomechanical study aimed to assess the biomechanical characteristics of three techniques-modified Kessler (mKE), modified Krackow (mKR), and modified tension Bunnell (mtBU)-in sheep Achilles tendon tear repair using three suture types-polypropylene, polyester, and ultra-high-molecular-weight polyethylene (UHMWPE)-which are also compared.

Sixty-three Achilles tendons harvested from sheep were transversely hacked as a replacement for rupture in a standardized measure and repaired using mKE, mKR, and mtBU techniques with No. 2 polypropylene, polyester, and UHMWPE sutures. Biomechanical parameters, such as Young's modulus, ultimate strength, and strength to the 5-mm gap, were recorded for statistical analysis.

The mtBU technique with UHMWPE use resulted in increased ultimate strength, strength to 5-mm gap, Young's modulus, and quantity of specimens with low clinical failure modes compared with the other techniques with other suture materials. Furthermore, mtBU has the lowest thickness at the repair side of the tendons. This approach showed tendon failure during maximal traction testing, whereas the mKE and mKR techniques had polyethylene and polyester suture failures.

The UHMWPE suture was significantly superior to the other sutures in each technique in terms of strength and durability. The mtBU technique using UHMWPE suture showed better biomechanical results, implying that this repair might be more appropriate to obtain early mobilization after tendon ruptures.