Objective: To determine a hand-tied ligature knot configuration, suture size, and suture type that would be an acceptable substitute to commercially available ligature knots for use in equine laparoscopic surgery.
Study design: Three-factor ANOVA with the fixed effects being suture type, suture size, and knot type. The dependent variable was ligature security (load to failure).
Methods: Commercially available Endoloop and 4 hand-tied slipknot ligatures were compared with a 4-layer square knot. The hand tied ligature knots tested were the 4S modified Roeder knot, the Brooks knot, the modified Roeder knot, and the Weston knot. Two suture sizes (0, 2) of each of 2 suture types (polydioxanone, polyglactin 910) were tested with each hand tied knot. Two types (polydioxanone, polyglactin 910) of size 0 Endoloop were tested. Twenty repetitions of each knot suture type were tested for force to yield on a materials testing machine. Statistical analysis consisted of a 3-way ANOVA with individual comparisons made using the Bonferroni method. Significance was P< or = .05.
Results: Only the 4S modified Roeder knot in 2 polydioxanone (103 N) was comparable with the breaking strength of the square knots (157 N). All other knot suture combinations tested were significantly weaker than the square knot (range, 2-18 N).
Conclusion: For equine laparoscopy, a 2 polydioxanone 4S modified Roeder knot would be an acceptable alternative to the commercially available Endoloop.
Clinical relevance: Laparoscopic slip knots are commonly used in equine laparoscopic surgery. Various knot configuration and suture size and type combinations will affect the security of the slip knot.