Research on effects of pulling direction on knot security during knot tying

GUO Hong-feng; HOU Xiao-yu; DAI Wei-wei; LIAO De-zhi; WEN Can

doi:10.19538/j.cjps.issn1005-2208.2025.04.16

Abstract：Objective To determine the effects of pulling direction on knot security during knot tying.Methods A research on knot tying was conducted at Department of Basic Operative Surgery,Army Medical University in September 2022.Knots were tied by the same person with the hands pulling in constant direction or in alternate directions,respectively.All knots were tied using silk suture in 3-0 gauge.For each kind of knots with 2-7 throws,100 knots were tied.A tensiometer was used to measure the tensile strength of the knots.Compare the tensile strength and untying rate of knots with different throws produced by two different cable pulling methods.Results For knots with 2-7 throws,the tensile strength of the ones tied by pulling in constant direction was lower than that of the ones tied by pulling in alternate directions,respectively.Besides,the knots with 5 throws tied by pulling in constant direction did not achieve the maximum tensile strength(22.0±7.3)N,while those tied by pulling in alternate directions achieved the maximum tensile strength(26.5±3.1)N.For knots with 3-7 throws,the untying rate of the ones tied by pulling in constant direction was higher than that of the ones tied by pulling in alternate directions,respectively.Besides,the knots with 5 throws tied by pulling in constant direction did not achieve the minimum untying rate(33％),while those tied by pulling in alternate directions achieved the minimum untying rate(10％).For the unraveled knots with 2-5 throws,the tensile strength of the ones tied by pulling in constant direction was lower than that of the ones tied by pulling in alternate directions,respectively.The unraveled knots with 5 throws tied by pulling in constant direction was just(12.2±3.7)N,while those tied by pulling in alternate directions could reach(18.9±4.5)N.Conclusion Pulling in constant direction results in inferior knot security.Although it could be compensated by increasing the throw count,considering that suture was foreign body,it is advisable to achieve superior security with fewer throw count.