Biomechanical Evaluation of a Novel Double-Strand (Looped) Polyamide Monofilament Suture for Canine Flexor Tendon Repair

Objective: Determine the influence of a novel looped polyamide suture on the biomechanical properties and gap formation of repaired canine flexor tendons. Study Design: Tendons were assigned to 3 groups (n=12/group). Following transection, tendons were repaired with a Kessler pattern using monofilament polypropylene, Kessler pattern using looped polyamide suture and a Kessler pattern using looped polyamide augmented with a continuous Epitendinous Suture (ES) representing groups 1, 2, and 3 respectively. Constructs were tested to simulate clinical failure. Yield, peak and failure loads, loads at -1 and 3mm gap formation and failure modes were analyzed. Results: Looped polyamide suture is equivalent to monofilament polypropylene using a Kessler core pattern. Looped polyamide suture augmented with a running ES significantly increased yield, peak and failure loads by 3.2x, 3.0x and 2.6x respectively, compared to core suture use alone. Use of an ES required significantly greater force to cause 3mm gap formation while reducing occurrence of gapping in tested constructs. Mode of failure differed among experimental constructs. Conclusion: Looped polyamide suture is equivalent to monofilament polypropylene in the same pattern. Our results support the addition of ES augmentation, a simple technique modification that demonstrates substantially improved repair strength while reducing the occurrence of gapping between tendon ends. Future in-vivo studies investigating effect of suture placement on tendinous healing, blood supply, and glide function are warranted.