Performance and Strength Characteristics of Suture Knots in Periodontal Microsurgery: An In Vitro Study

Area of Science:

• Surgical Materials Science
• Biomedical Engineering
• Surgical Knot Tying

Background:

• Surgical knot security is critical for successful wound closure and preventing complications.
• Understanding knot failure modes (untying vs. breaking) and factors influencing them is essential for surgical practice.

Purpose of the Study:

• To investigate the failure types (untying or breaking) of surgical knots.
• To determine the tension required to break polyamide sutures of varying diameters (6/0, 7/0, 8/0).
• To analyze the impact of knot configuration and number of throws on knot security and tensile strength.

Main Methods:

• Fabrication of 150 polyamide suture knots with diameters 6/0, 7/0, and 8/0.
• Knot configurations included squared and slipped types with 2 to 6 throws.
• Standardized device and weights were used for knot creation and controlled tension testing, recording failure type, tension, slippage, and elongation.

Main Results:

• Knots with configurations 1=1, 1×1, 2=1, and 2×1 untied, while others broke.
• A minimum of three throws (e.g., 1=1=1 or 1×1×1) was necessary to prevent untying.
• Mean breaking tensions for 6/0, 7/0, and 8/0 sutures were 3.1 N, 1.3 N, and 0.6 N, respectively (P < .05), independent of knot type.
• Secure knots (2=2/2×2, 1=1=1/1×1×1) did not gain security from additional throws.

Conclusions:

• Specific knot configurations (e.g., 1=1=1, 1×1×1) are essential for preventing surgical knot untying.
• Tensile strength is significantly reduced in smaller diameter sutures (6/0, 7/0, 8/0).
• Excessive throws beyond a certain point do not enhance the security of inherently stable knot designs.