Assessment of knot security in continuous intradermal wound closures

Abstract

The traditionally used square knot used for commencement and termination of continuous wound closures is bulky, requiring a minimum of four to six throws to form a secure knot with most suture materials and sizes. This study evaluates the security of self-locking knots, which are significantly smaller in volume than the traditionally applied square knot, for the intradermal closure of standardized wounds in porcine skin. Porcine skin samples with standardized wounds were closed in one of five patterns with 3/0 PDS suture. Wounds were harvested and tested to failure on a materials testing machine. Load at failure, ultimate elongation, wound stiffness, and mode of failure was determined for each sample. Wound closures incorporating the chain stitch knot performed as well as closures incorporating the conventional square knot for load to failure, elongation, and stiffness. Partial slippage or complete knot failure of 4/40 (10%) of the square knots used in closures was observed. 0/20 (0%) of the chain stitch knots displayed slippage. The half-blood knot performed similarly to the square and chain stitch knot in load to failure, elongation, and stiffness, however, 16/20 (80%) of these knots displayed slippage or complete knot failure. The chain stitch knot is as secure as the traditionally used square knot when used for termination of a continuous intradermal wound closure. This knot displays characteristics such as smaller knot volume and ease of applications that may make it a superior knot to the square knot in many clinical situations.