In Vitro Evaluation of the Size, Knot Holding Capacity, and Knot Security of the Forwarder Knot Compared to Square and Surgeon's Knots Using Large Gauge Suture

Abstract

To investigate the strength, size, and holding capacity of the self-locking forwarder knot compared to surgeon's and square knots using large gauge suture. In vitro mechanical study. Knotted suture. Forwarder, surgeon's, and square knots were tested on a universal testing machine under linear tension using 2 and 3 USP polyglactin 910 and 2 USP polydioxanone. Knot holding capacity (KHC) and mode of failure were recorded and relative knot security (RKS) was calculated as a percentage of KHC. Knot volume and weight were assessed by digital micrometer and balance, respectively. ANOVA and post hoc testing were used tocompare strength between number of throws, suture, suture size, and knot type. P<.05 was considered significant. Forwarder knots had a higher KHC and RKS than surgeon's or square knots for all suture types and number of throws. No forwarder knots unraveled, but a proportion of square and surgeon's knots with <6 throws did unravel. Forwarder knots had a smaller volume and weight than surgeon's and square knots with equal number of throws. The forwarder knot of 4 throws using 3 USP polyglactin 910 had the highest KHC, RKS, and the smallest size and weight. Forwarder knots may be an alternative for commencing continuous patterns in large gauge suture, without sacrificing knot integrity, but further in vivo and ex vivo testing is required to assess the effects of this sliding knot on tissue perfusion before clinical application.