A Mechanical Analysis of Zhang’s knot, a New Slip Knot with Locking Mechanism

Abstract

Abstract Background: An effective knot, which is used under the arthroscopy, must possess the optimal balance of knot security and loop security. The aim of this research was to assess the biomechanical performance of the Zhang’s knot, a new slip knot, comparing with Tennessee knot, Roeder knot, and SMC knot. Methods: The Zhang’s knot and other 3 arthroscopic sliding knots (Tennessee knot, Roeder knot, and SMC knot) were tied with 3 reversing half-hitches on alternating posts (RHAPs) following. A total of 60 specimen of 5 different types of knots were assessed, with the static surgeon’s knot as comparison. The knots were tied around a 30 mm circumference plastic post for a unified 30 mm loop circumference before locking the complex knots by tensioning the wrapping limb of the suture. The loop security (the capacity of knot maintaining a tight suture loop without slippage) was assessed based on the circumference of knots under 5 N preload; the knot security was assessed based on the maximum force to failure at 3 mm of crosshead displacement or suture breakage during single-pull load testing. Results: Regarding the loop circumferences, under 5 N preload, the Zhang’s knot was not significantly different from Tennessee knot (P = 0.396), but smaller than SMC knot (P = 0.029), Roeder knot (P = 0.007) and surgeon’s knot (P = 0.007). In term of load-to-failure, the Zhang’s knot was not significantly different from Tennessee knot (P = 0.077) and SMC knot (P = 0.903), but stronger than Roeder knot (P = 0.030) and surgeon’s knot (P < 0.001). Conclusions: The Zhang’s knot is easily reproducible and shows a great balance of loop security and knot security just as Tennessee knot with 3 RHAPs.