33rd Annual Scientific Meeting proceedings

Introduction
Cats with Achilles tendon rupture more commonly suffer tendino-osseous avulsions from the tuber calcanei compared to dogs (Voss 2009). Reinsertion of the avulsed tendon to the calcaneus through a bone tunnel was recommended as treatment of choice (Cervi 2010). The goal of this study was a mechanical comparison between classical bone tunnel anchorage and Weldix anchor fixation.

Materials and methods
Seven pairs of gastrocnemius tendon-calcaneus blocks were harvested from cats (death unrelated to study). Gastrocnemius tendons were reinserted to the calcaneus either through a transverse bone tunnel or using a Weldix suture anchor with Prolene 2/0 in a Bunnell-Mayer pattern. Tensile tests were conducted on all samples at a displacement rate of 20 mm/min until failure on a servo-electric load-frame (SELmini-001, Thelkin, Switzerland). Gap formation was tracked with a video camera and results compared with paired t-tests.

Results
Mean loads at a gap of 0.5 and 1 mm respectively were significantly higher for the Weldix anchor (44.2±5.5 N and 51.3±9.3 N) compared to bone tunnel fixation (23.0±15.4 N and 28.6±17.1 N). A 3 mm gap was not reached with the Weldix anchor. Failure loads were not significantly different between the Weldix anchor (55.2±8.0 N) and bone tunnel fixation (65.1±8.3 N). Mode of failure was suture breakage in most cases, pulling through the tendon substance did not occur.

Discussion/Conclusion
The Weldix suture anchor required higher loads for gap formation compared to a classical bone tunnel and can be considered advantageous for Achilles tendon reinsertion in cats.