Evaluation of the in vitro performance of the double forwarder knot, compared to square and surgeon's knots using large gauge suture
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Published on: October 26, 2019
Harriet K Barnes1, Amelia S Munsterman2, Alex M Gillen1
1Philip Leverhulme Equine Hopsital, University of Liverpool, Neston, UK.
Objective:
The aim of the study was to evaluate the strength and size of the double forwarder (DF) knot in 2 and 3 USP polyglactin 910 when used to form a ligature and to compare the knot holding capacity (KHC), size and weight of the DF knot to surgeon's (SU) and square (SQ) knots with varying numbers of throws.
Study Design:
Laboratory study.
Study Population:
Knotted suture.
Methods:
Knots were tied using 2 and 3 USP polyglactin 910 and tested on a universal testing machine under linear tension. Mode of failure and (KHC) were recorded. Knot volume and weight were determined by digital micrometer and balance. KHC, size, and weight between knot type, number of throws, and suture type and size were compared using ANOVA testing, with p < .05 as significant.
Results:
In both suture types, DF knots had a higher KHC than SQ/SU knots (p < .004), with the exception of SU knots with 6-8 throws in 3 USP polyglactin 910 (p > .42). All DF knots failed by suture breakage at the knot, as did all SQ/SU knots with >6 throws. DF knots in 2 and 3 USP polyglactin 910 were larger and heavier than SQ and SU knots when the same number of throws was applied (p < .003).
Conclusion:
Self-locking DF knots provided increased strength compared to SU/SQ in large gauge suture but only when fewer than six throws are applied to SU/SQ knots.
Clinical Relevance:
The new DF knot could be an alternative for a secure ligature.
