Non-suture repair of tendons

A set of metal clamps cooled by liquid nitrogen were developed to hold the ends of tendons during in vitro tension tests. These were then used to determine the strength of whole human tendons, and human tendons repaired in vitro by sutures or by cyanoacrylate glues with or without suturing. The mean ultimate load of the intact human tendons was 1065 N, and the ultimate stress was 99.02 MN m-2. The repairs gave values of 0.3-2.3% of those of intact human tendon. Tendons were then repaired in vivo by a Kessler suture technique using braided polyester sutures with or without augmentation by a butyl cyanoacrylate glue (Histoacryl). At six months post-repair all tendons were as strong as the unoperated contralateral tendons. The glue augmented sutures were stronger than those not so augmented. A scanning electron micrograph of a tension tested glued tendon showed that it had failed by cohesive failure, i.e. failure of the inter-glue bonds rather than failure at the glue/tendon interface.