Ex-Vivo Evaluation of a Modified Teno Fix(®) Device Repair Pattern Versus a 3-Loop Pulley for Repair of Equine Flexor Tendons.

The research article is a comparative study of the Teno Fix(®) (TF) device versus the 3-loop pulley (3LP) for repairing equine tendon tears. The study particularly investigates their strength under certain loads and situations.

Research Methodology

The researchers carried out an ex vivo biomechanical study using an unbalanced incomplete block design on horse cadavers. Specifically, they used twenty paired tendons from cadaveric equine forelimb superficial digital flexor.

• Ten of these tendon pairs were selected randomly and repaired with a 3LP and 4TF pattern.
• The other ten tendon pairs were repaired with a 3LP and 5TF pattern.

The researchers then tested these repaired tendons to measure their load to ultimate failure, load to a 2mm gap (the force required to create a 2mm gap in the repair), the mode of failure (how the repair failed), and the gap at failure (the size of the gap in the repair when it failed).

Study Findings

The findings revealed that the 3LP had a significantly greater ultimate load to failure and a higher load to a 2mm gap than both TF repairs. This implies that 3LP repairs are stronger and thus more resistant to strains that could cause them to fail.

The most common mode of failure differed between the two repair types. In the 3LP repairs, the suture tended to pull out, whereas in the TF repairs, the anchor tended to pull out. Meanwhile, the gap at failure was notably larger in the 3LP repairs than both TF repairs, indicating that the relative mode of failure could lead to more significant damage.

Notably, the load to ultimate failure was substantially higher for the 5TF repairs than the 4TF repairs, indicating that adding a fifth TF device made the repair stronger. However, there was no significant difference in load to a 2mm gap, or gap at failure, between both TF repairs, suggesting that adding a fifth TF device did not influence the repair’s ability to withstand strain or the extent of damage at the point of failure.

Conclusion of the Study

Overall, the findings show that neither TF repair was stronger than the 3LP repair in terms of load to ultimate failure and load to a 2mm gap. The addition of a fifth TF device considerably increased the load to ultimate failure but did not affect the load to a 2mm gap over the 4TF. Therefore, while a 5TF pattern may hold up better under load, it’s not any less likely to develop a gap under strain than the 4TF pattern. Hence, the choice between these repair methods might depend on other factors, like the specific situation of the equine patient, surgeon preference, or resources available.