Effect of insertion process on biceps tendon reconstruction in BASHTI technique: An in-vitro study

BASHTI implant-less technique has been proposed as an alternative to conventional tendon repair methods. This study aims to evaluate the strength of this technique under biceps loading conditions with different fixation strategies. Twelve specimens with bovine tendons and Sawbones were constructed using two different insertion methods; in Group 1, 4 samples were prepared using a hand-hammer with a hitting frequency of 300 beats per minute (BPM), while Group 2 included eight specimens with insertion using an auto-hammer applying a frequency of 3600 BPM. Both groups were tested under a cyclic loading followed by a pull-out until the failure. All the samples completed the cyclic step without failure. At the pull-out step, for Group 1, the strength was 251±31 N, and the stiffness was 10.3±0.8 N/mm, while these values were 183±35 N and 10.5±3.0 N/mm, respectively for Group 2. It was concluded that the BASHTI structure for biceps tendon reconstruction had a suitable strength and the insertion process had no effect on its behavior under cyclic loading. It was also proved that variations in the insertion frequency significantly affect the structure's maximum strength (p-value = 0.038). Still, its influence on the stiffness was insignificant (p-value = 0.91).