Does Knot Configuration Improve Tensile Characteristics of Monofilament Suture Materials?

Abstract

The effects of knot configuration used in surgical procedures are often overlooked when surgeons are looking for an ideal suture material. This study aimed to investigate the mechanical properties of monofilament suture materials used in oral and maxillofacial surgery under diverse knot configurations. A custom-made experimental platform and a microtensile test device were used to evaluate the mechanical properties of the tested subjects. There were 2 predictor variables: suture material and knot configuration. Three types of nonabsorbable and monofilament suture materials with 4-0 gauge, including nylon, polypropylene, and polytetrafluoroethylene, were tested. Four different knot configurations-a surgeon's knot square plus a square knot (2=1=1), a surgeon's knot granny plus a square knot (2×1=1), a reverse surgeon's knot granny plus a square knot (1×2=1), and a reverse surgeon's knot square plus a square knot (1=2=1)-were also used with each of the suture materials. The tensile strength (N) and elongation (μm) of each sample were measured as the outcomes. The data were statistically analyzed using 2-way analysis of variance and Tukey's honestly significant difference tests. The significance level was set at P<.05. Overall, 120 samples were tested. Statistical analysis revealed that the highest tensile strength (28.6N) was found for nylon in the surgeon's knot square plus a square knot (P<.05). Polypropylene showed a similar high tensile strength value (24.7N) in the reverse surgeon's knot granny plus a square knot (P>.05). Polytetrafluoroethylene demonstrated significantly lower values for both tensile strength in tested configurations (within the range of 5.2-8.5N). Under diverse configurations, polypropylene suture samples offered the most stable tensile strength and elongation. The present study demonstrated that different knot configurations might improve the mechanical profile of commonly used monofilament suture materials. The surgeon's knot square (2=1), commonly used by surgeons worldwide, proved to be the most beneficial knot configuration in this study in terms of tensile strength and elongation. Further research on optimal knot configuration may be just as important as seeking an ideal suture material.