Comparison of Tensile Properties and Knot Security of Surgical Sutures: An In Vitro Mechanical Study.

Purpose: Studies on the mechanical properties and knot security of smaller sutures used in oral and maxillofacial surgery are limited. The objective of this study is to measure the tensile properties and knot security depending on the suture materials, knotting techniques, and number of throws using 5-0 sized sutures.

Methods: Seven 5-0 sized sutures were measured in both straight-pull and knot-pull according to the procedures outlined by the United States Pharmacopeia. Regarding knot security, there were 3 predictor variables: suture material, knot technique, and number of throws. Two surgical tying techniques were square knot and surgeon's knot and the number of throws were 3, 4, and 5. One-way analysis of variance was applied to test tensile properties (α = 0.05). The dichotomous outcome of knot security (stable or unstable) was analyzed using logistic regression analysis and odds ratios with Tukey-adjusted 95% confidence intervals.

Results: Ethicon polyglactin 910 was found to have the highest failure load (18.0 N) of straight, while silk sutures had the lowest of both straight and knotted. A higher elongation rate was found in the 2 monofilament suture materials polypropylene and polydioxanone. Knot security depended on the suture technique, material, and number of throws. Surgeon's knots were stronger than square knots. The number of throws required to achieve knot security depends on the specific combination. For polypropylene or Jinhuan silk with the surgeon's knot, 3 throws can probably achieve knot security.

Conclusions: The new data presented in the study provided important information for guiding the selection of smaller suture materials for oral and maxillofacial surgery. A wider range of suture combinations should be tested, and more in vivo studies are needed to clarify the characteristics of sutures and knots.