In Vitro Biomechanical Testing of the Tube Knot

Area of Science:

• Biomedical Engineering
• Materials Science
• Surgical Research

Background:

• Surgical knots are crucial for wound closure and device fixation.
• Evaluating the biomechanical properties of different knotting techniques is essential for optimizing surgical outcomes.
• The tube knot (TB) offers an alternative to traditional square knots (SQ) and mechanical devices like crimp clamps (CC).

Purpose of the Study:

• To compare the in vitro biomechanical properties of the tube knot (TB) against a crimp clamp (CC) system and a square knot (SQ).
• To assess the influence of three distinct monofilament materials on the performance of each knotting method.

Main Methods:

• An in vitro biomechanical study was conducted using suture loops (n=20 per material/knot construct).
• Knots were created using three methods: tube knot (TB), 5-throw square knot (SQ), and crimp clamp (CC) system.
• Three monofilament materials were tested: 40# Securos® nylon, #2 polypropylene, and #2 nylon.
• Monotonic tensile loading was applied to determine ultimate tensile strength, elongation at failure, and stiffness, with data analyzed using ANOVA.

Main Results:

• Ultimate tensile strength varied significantly by both material and knotting method.
• The 40# nylon crimp clamp (CC) exhibited the highest ultimate tensile strength, closely followed by the tube knot (TB), with no significant difference between them.
• The tube knot (TB) and square knot (SQ) showed significantly greater elongation at failure compared to the crimp clamp (CC), particularly with 40# nylon.

Conclusions:

• The tube knot (TB) offers biomechanical strength equivalent to the crimp clamp (CC) system.
• However, the significantly greater elongation at failure observed with the tube knot (TB) may raise concerns for specific clinical applications requiring high stiffness and minimal deformation.