In vitro evaluation of square and surgeon's knots in large gauge suture.

Abstract

OBJECTIVE: To investigate the strength and size of surgeon's and square knots for starting and ending continuous suture lines using large gauge suture. STUDY DESIGN: In vitro mechanical study. STUDY POPULATION: Knotted suture. METHODS: Surgeon's and square knots were tested using 2 and 3 USP polyglactin 910 and 2 USP polydioxanone under linear tension on a universal testing machine. Failure mode and knot holding capacity (KHC) were recorded, and relative knot security (RKS) was calculated as a percentage of KHC. Comparisons were made between number of throws, suture size, suture type, and knot types. Knot volume and weight were assessed by a digital micrometer and balance, respectively. RESULTS: There were no significant differences in KHC (P&#x2009;=&#x2009;.295), RKS (P&#x2009;=&#x2009;.307), volume (P&#x2009;=&#x2009;.128), or weight (P&#x2009;=&#x2009;.310) between square and surgeon's knots at the start or end of suture lines with the same number of throws and suture type. A minimum of 6 throws were required for start knots and 7 throws at end knots to prevent unraveling. Knots tied with 3 polyglactin 910 were strongest (P&#x2009;<&#x2009;.001) and 2 polyglactin 910 produced knots with higher KHC and RKS than 2 polydioxanone (P&#x2009;<&#x2009;.001). CONCLUSION: No consistent differences were detected between knots types tied with the same suture material; however, number of throws affected KHC and RKS up to 6 throws in start or 7 throws in end knots. The configuration of square and surgeon's knots performed at the end of a continuous line alters their KHC, supporting the use of additional throws for knot security.