An In Vitro Study Assessing the Effect of Fluid Media on the Mechanical Properties of Pattern Starting and Ending Surgeon’s, Square and Aberdeen knots

Abstract

The objective of this study was to investigate the knot holding capacity (KHC) of pattern starting and ending square, surgeon’s and Aberdeen knots each tied in 4 throw combinations using either 2USP polydioxanone or 3USP polyglactin 910 after exposure to media commonly found in equine abdominal surgery. An In vitro mechanical study was performed Strands of 2USP polydioxanone or 3USP polyglactin 910 were exposed to one of four media for 15 minutes. The control suture strands remained dry. The media used included a balanced electrolyte solution, 1% sodium carboxymethylcellulose, equine serum or equine fat. Pattern starting knots and pattern ending knots were loaded to failure in a linear fashion on a materials testing machine to determine KHC. Start knots tied using either suture exposed to media and end knots tied with 3USP polyglactin 910 had a significantly higher KHC than those tied in dry conditions. No increases in KHC were seen with either suture material used to tie start knots over 5 throws and end knots over 6 throws when suture was exposed to media. Pattern ending surgeon’s knots tied using media exposed 3USP polyglactin 910 had a significantly higher KHC than the same dry knots with 5 and 6 throws. Pattern ending square knots tied using media exposed 3USP polyglactin 910 had a significantly higher KHC than the same dry knots at 5 throws. Aberdeen knots tied with either media exposed 2USP polydioxanone or 3USP polyglactin 910 had a significantly higher KHC than their equivalent dry knots. Aberdeen knots had a superior KHC, while requiring less suture than both surgeon’s and square knots. Media exposure either had no effect on KHC, or significantly improved the KHC of all the knots investigated. The most suitable start knot for a continuous pattern closure of the equine linea alba is the surgeon’s knot tied using 3 USP polyglactin 910, with 5 throws. Aberdeen knots tied using media exposed 3USP polyglactin 910 with 3 throws and 1 turn are recommended to end the continuous suture pattern.