The mechanical interaction between three geometric types of nylon core suture and a running epitenon suture in repair of porcine flexor tendons

The effect of core suture geometry on the mechanical interaction with the epitenon suture in terms of gap prevention, failure strength and mode of failure was investigated in a flexor tendon repair model. A total of 48 porcine flexor tendons were repaired using three techniques with distinct core suture geometry: single Kessler; double Kessler; and cruciate repair. Cyclic linear testing was carried out with and without a simple running epitenon suture. At failure load the epitenon suture reduced gapping by 87% in the double Kessler, 42% in the single Kessler and 15% in cruciate repairs. It increased the strengths of the repairs by 58%, 33% and 24%, respectively. Kessler repairs failed mainly by suture rupture, with and without epitenon suture, but cruciate repairs failed mainly by suture pull-out. The epitenon suture did not have a significant mechanical effect on the three repairs. Rather, its effect varied with the core suture geometry. The greatest effect occurred with double Kessler repairs.