Biomechanical evaluation of double stranded knot configurations in high strengths sutures and tapes

Abstract Purpose: Recently, a new dynamic high-strength round suture (DC) was introduced featuring a salt-infused silicone core attracting water in a fluid environment to preserve tissue approximation which is also available in tape form (DT). The aims of this study were to (1) assess the influence of securing throw number on knot security of two double-stranded knot configurations (Cow-hitch and Nice-knot) tied with either dynamic (DC and DT) or conventional round sutures (FW) and conventional suture tapes (ST), and (2) compare the ultimate force and knot slippage of (a) Cow-hitch and Nice-knot and (b) DC and DT versus FW and ST when used with their minimal number of needed securing throws. Methods: Seven specimens of each FW, ST, DC and DT were considered for tying with Cow-hitch or Nice-knots. The base of these Cow-hitch and Nice-knots were secured with surgeons’ knots using 1–3 alternating throws. Tensile tests were conducted under physiologic conditions to evaluate knot slippage, ultimate force at rupture, and minimum number of throws ensuring 100% knot security. Results: For both Cow-hitch and Nice-knots, 100 % security was achieved with 2 securing throws for DC, DT, ST, and with 3 securing throws for FW. With these minimum numbers of securing throws, ultimate force was significantly higher for Nice-knots versus Cow-hitch tied with DT (p=0.001) and slippage was significantly less with Nice-knots versus Cow-hitch tied with DC (p=0.019). Conclusions: The minimum number of securing throws required to achieve 100% security was 2 with DC, DT and ST for both with Cow-hitch and Nice-knots configurations, in contrast to FW where 3 securing throws were needed. With these minimum numbers of securing throws, Nice-knots were associated with significantly higher ultimate forces when using DT and lower slippage with DC versus Cow-hitch knots.