The effect of knotting method on the structural properties of large diameter nonabsorbable monofilament sutures

Objective-To evaluate the effect of knotting method on the mechanical prope rties of large diameter nonabsorbable monofilament suture materials. Study Design-In vitro mechanical evaluation. Methods-A conventional square knot was compared with the surgeon's knot, sl iding half-hitch, and clamped square knot. Knotted suture loops were create d in a uniform manner and acutely tensioned to failure (20 mm/min loading r ate; n = 20 per knot type for each material). Stiffness, yield, and failure characteristics of USP #2 nylon, #2 polybutester, #2 polypropylene, 27 kg test monofilament nylon fishing line, and 27 kg nylon leader material were evaluated. Results-Compared with a conventional square knot, a surgeon's knot decrease d stiffness for #2 polypropylene, 27 kg fishing line, and 27 kg leader (P < .05). A sliding half-hitch weakened all materials except 27 kg leader (P < .05). Clamping the first throw of a square knot increased the stiffness of 27 kg leader loops (P < .05). Conclusions-Based on clinically relevant parameters (stiffness and yield), knotting method had no effect on #2 nylon and #2 polybutester. The surgeon' s knot is not recommended for #2 polypropylene and 27 kg fishing line and l eader material. A sliding half-hitch decreased the yield of lender material . Clamping the first throw of a square knot had no adverse effects on acute properties of tested materials; it increased the stiffness for leader mate rial. Clinical Relevance-Knotting method does influence the structural properties of suture materials and should be considered when tying knots under tensio n. (C)Copyright 1999 by The American College of Veterinary Surgeons.