How to convert a square knot or surgeon's knot into a sliding knot and an assessment of their sliding and re-locking properties?

Abstract

Background and purposeIt is generally believed that a tight square knot or a surgeon's knot cannot be easily loosened. The objectives of this study were to explore a magic-trick-based rapid unlocking technique for tying a surgical knot, which allows restoration of the bi-directional movement of an unmovable locked knot. Material and methodsThe suture knots used included 2- and 3-throw square knots and surgeon's knots with different suture materials. The loops of four knots of various materials were tightened using the unlocking technique under simulated bone friction coefficient conditions, and the loops were observed for complete fastening of the humeral specimens. The drag forces of knot sliding (DFKS) used for different materials and different knot configurations were measured using a digital force gauge. Statistical analysis of the differences in DFKS between different knot configurations with different suture materials was performed. Main findingsExcellent loop tightening effects could be achieved for the arbitrary combination of nine sutures and four knots using this technique. The DFKS of the various knot configurations, with the same material, were as follows: 2 = 1 = 1 > 1 = 1 = 1 > 2 = 1 > 1 = 1, the DFKS of different sizes followed the order 0 silk > 2-0 silk > 3-0 silk; 0 Vicryl Plus > 2-0 Vicryl Plus > 3-0 Vicryl Plus. The DFKS for all sutures was less than 0.5 kgf. ConclusionThe rapid knot unlocking (RKU) technique can unlock any one of the double-stranded types of traceless knot. The suture loop tension can be adjusted at will. Bi-directional movement of the fast knot and the re-locking of sliding knot are solved.