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Flat square knots: are 3 throws enough?
Tracy Behm1, James B Unger, Joseph J Ivy
1Division of Gynecologic Pelvic Surgery, Department of Obstetrics and Gynecology, Louisiana State University Health Sciences Center, Shreveport, LA, USA.
Objective:
The objective of the study was to determine the integrity of flat square knots.
Study Design:
Three sutures were used in both 0 and 2-0 suture gauges: poliglecaprone 25 (Monocryl), polyglactin 910 (Vicryl), and silk. For each, flat square knots were tied with either 3 or 5 throws. Knots were tested to failure. The major outcome measured was the proportion of 3 throw knots untying, compared with that of 5 throw knots.
Results:
There were high rates of untying for the poliglecaprone 25 and for the polyglactin 910 with both suture gauges when tied with only 3 throws. The failure rate decreased significantly when the throws were increased. There was no statistical benefit to increasing the number of throws for silk.
Conclusion:
Knot failure is decreased by increasing the number of throws for poliglecaprone 25 and polyglactin 910. However, there is no advantage to increasing the number of throws from 3 to 5 for silk.
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