Technical considerations in knot construction, part III. knot asymmetry

Assessment of knot security in continuous intradermal wound closures

“…Properly formed square knots can be converted into a series of half-hitches when uneven tension is applied to the suture ends, particularly with monofilament materials [8]. The square knot has been shown to be prone to failure by slipping [6], especially when the penultimate loop is incorporated in a square knot, as in the termination of a continuous suture line closure [1,7]. Depending on the suture material and size used, square knots have been shown to require an additional two to three throws on top of the initial knot (four to five throws total) to produce a secure knot [7].…”

“…The square knot commonly used to start and complete a suture line is bulky, requiring four to six throws to form a secure knot for most suture materials [1,6]. This can result in a knot that may protrude to the surface and cause problems with wound healing, excess patient discomfort, and sub-optimal cosmetic appearance in subcutaneous and subcuticular closures [11].…”

Variability of surgical knot tying techniques: do we need to standardize?

“…In order to establish the safety characteristics of different suture materials and the corresponding knot tying techniques, many authors used technical devices and even electron microscopy [6,7,15,30,[38][39][40]. These devices, it is true, provided solid information on issues such as breaking strength and slippage, but the translation of such findings into clinical application is problematic.…”

Measuring the strength of knotted suture materials

“…In the cut-loop method a loop is formed as in the loop method, however the knotted suture loop is cut opposite the knot and each newly formed end is placed in a jaw of a tensile tester (Huber et al, 1999;Lewis, Milthorpe, & Bellenger, 1997;Rodeheaver, Green, Odum, Bussard, & Edlich, 1998;Rosin & Robinson, 1989;Schiller, Stone, & Gupta, 1993;Tera & Aberg, 1976a;Thacker et al, 1975). Although the load is applied to the patient's side, the cutloop technique usually measures knot slippage rather than knot strength, the measured values being affected by the length of the ears.…”

“…8 mm loop (Nilsson, 1982), 36 mm (Rosin & Robinson, 1989), 38 mm (Tera & Aberg, 1976a), 50 mm (Magilligan & DeWeese, 1974), 80 mm (Annunziata et al, 1997), and one test speed (e.g. 6 mm/min [Gerber, Schneeberger, Beck, & Schlegel, 1994], 10 mm/min [Herrmann, 1971], 20 mm/min [Huber et al, 1999], 50 mm/min [Rodeheaver et al, 1998], 60 mm/min [Tera & Aberg, 1976a], and 75 mm/min [Nilsson, 1982]). Previous research involving knotted sutures has concentrated on identifying tensile properties of specimens prepared using different knots.…”