Beyond the square knot: a novel knotting technique for surgical use

Knot holding strength is essential to maintain wound closure and ensure tissue contact for healing. Knot unraveling can lead to severe complications, especially for high-tension closures such as tendon repairs, which have recently been reported to have knot unraveling rates as high as 86%. In the current study, a novel surgical knot, the two-strand-overhand locking (TSOL) knot, was designed and mechanically evaluated with use of different suture materials and knot configurations and in actual tendon repairs.

The knot holding strength of the TSOL knot was compared with that of a 4-throw square knot with use of three different suture materials that are in common clinical use. With use of braided polyblend suture, the TSOL knot was also compared with five other surgical knot configurations. Finally, the strength of tendon repairs performed with use of the TSOL knot and a 4-throw square knot was studied.

Compared with the 4-throw square knot, the holding strength of the TSOL knot was 143% greater for braided polyblend, 216% greater for polydioxanone, and 118% greater for polyester suture, with a significantly lower knot unraveling rate compared with that of the 4-throw square knot regardless of suture material. The TSOL knot holding strength was also greater than that of the other surgical knot configurations. The strength and stiffness of tendon repairs with a TSOL knot were significantly increased over those of repairs with a 4-throw square knot.

The TSOL knot provided superior knot holding strength compared with some commonly used surgical knots.

The TSOL knot has potential clinical applications, especially when knot security is important and high loads are expected, as in tendon or ligament repairs.