Elongation of Arthroscopically Tied Knots

Abstract

It has been postulated that some arthroscopic shoulder stabilization failures may be due to knot slippage. In an effort to improve arthroscopic technique, we performed tensile testing on four arthroscopically tied knots with two commonly used suture materials. Handtied square knots served as controls. Sutures of No. 1 Maxon and No. 1 Ticron were used. Four types of sliding knot configurations were tested: the overhand loop, the Duncan loop, the Roeder knot, and the Snyder knot. Knots were tied via a knot pusher, and testing was performed in a normal saline-filled thermoplastic chamber. Knots were tied around two rings connected to a Bionix 858 materials testing apparatus. The knots were tested under conditions of cyclic loading and loading to failure. Results of the testing revealed that the most important factor in knot security was the type of suture material, although there were differences with the type of knot. With the Maxon suture, there was significantly decreased ultimate failure load of all of the arthroscopically tied knots compared with handtied square knots. Knots tied with Ticron were similar in strength for both arthroscopically and handtied groups. The surgeon who chooses a monofilament absorbable suture should be aware that a high percentage of knots fail under low load cyclic testing, and that all of these knots were inferior to handtied square knot controls in testing to failure.

An in vitro analysis of the mechanical properties of 16 arthroscopic knots

“…1). The biomechanical testing model was adapted from the technique of Mishra et al [11] which included a pre-load phase, a cyclical loading phase, and an ultimate (failure) loading phase. All knots were first preloaded to 5 N to remove the slack and the loop length was recorded to calculate loop security.…”

“…The studies of Loutzenheiser et al and Mishra et al [11,13,14] were the first studies published that compared the biomechanical attributes of different arthroscopic knot configurations. Currently, the study that has compared the most number of knots head-tohead examined ten knots [4].…”

Ease of tying arthroscopic knots

“…Prior studies have examined the biomechanical properties of arthroscopic knots, 4,10,12,13,15,18 but no study has evaluated the ease of learning and tying them. This study revealed that the Tennessee slider, Duncan loop, Revo knot, and Nicky's knot were the easiest for the surgeons in training to learn and use.…”

Enhancing knot security by heat treatment of knot ears

“…These relatively large suture sizes are commonly used in various procedures in the repair of the shoulder. 3 A tied suture has three components. The loop created by the knot maintains the apposition of tissue.…”