Minimum number of throws needed for knot security

J Surg Educ. Mar-Apr 2011;68(2):130-3. doi: 10.1016/j.jsurg.2010.11.001. Epub 2010 Dec 28.

Abstract

Objective: The purpose of the study was to determine the optimal number of throws to ensure knot security.

Study design: Knots were tied with 3, 4, 5, or 6 square throws with 0-gauge coated polyester, polydioxanone, polypropylene, and polyglactin 910. The suture was soaked in 0.9% sodium chloride and subsequently transferred to a tensiometer and broken.

Results: A total of 225 knots were tied. Regardless of the suture type, tension at failure for knots with 4 throws, 5 throws, and 6 throws was higher than tension at failure of knots with only 3 throws (p < 0.05 for each). We found no difference in the tensile strength between knots with 4, 5, or 6 throws (p > 0.05 for each). Knots with 4 throws were significantly more likely to come untied than knots with 5 or 6 throws (p < 0.01).

Conclusions: Under laboratory conditions, the ideal knot has 5 throws to maximize tensile strength and rate of untying. This finding does not seem to vary by type of suture material.

Publication types

  • Comparative Study

MeSH terms

  • Humans
  • Materials Testing
  • Safety Management
  • Sensitivity and Specificity
  • Surgical Wound Dehiscence / prevention & control*
  • Suture Techniques / adverse effects
  • Suture Techniques / standards*
  • Sutures / adverse effects
  • Sutures / standards*
  • Tensile Strength