Interferometric Analysis of Knot Configurations Impact on Structural Properties and Mechanical Strength of Suture Materials

Despite of their ancient legacy, the knots used in modern surgery often rely more on tradition than on hard scientific evidence. While various knot configurations, like square and surgeon's knot are commonplace, their effectiveness and strength have not been thoroughly investigated until now. This study aimed to bridge this gap by analyzing the structural and mechanical properties of three common suture materials (Monocryl, Maxon, and Prolene) tied in two knots configurations (square and surgeon's knot). A Mach-Zehnder interferometer, in conjunction with a mechanical drawing device, was employed to gauge the birefringence in various knot configurations under varying stress levels by tracking the interaction of light with each knot. This provides valuable insights into the structure and stiffness of the knots. The structural and optical properties of the suture materials at the two knots configurations were calculated. The mechanical properties, such as Young's modulus (E), and mechanical loss percentage due to the different knot configurations were also calculated. The radial structure parameters and structure along various sutures were investigated by measuring the 3D refractive index at various knot configurations. The results shed light on the fact that Monocryl and Maxon sutures are stiffer than Prolene sutures. This confirms that suture material composition plays a role in its rigidity and handling characteristics.