ELONGATION OF ARTHROSCOPICALLY TIED KNOTS

It has been postulated that some arthroscopic shoulder stabilization f ailures may be due to knot slippage. In an effort to improve arthrosco pic technique, we performed tensile testing on four arthroscopically t ied knots with two commonly used suture materials. Handtied square kno ts served as controls. Sutures of No. 1 Maxon and No. 1 Ticron were us ed. Four types of sliding knot configurations were tested: the overhan d loop, the Duncan loop, the Roeder knot, and the Snyder knot. Knots w ere tied via a knot pusher, and testing was performed in a normal sali ne-filled thermoplastic chamber. Knots were tied around two rings conn ected to a Bionix 858 materials testing apparatus. The knots were test ed under conditions of cyclic loading and loading to failure. Results of the testing revealed that the most important factor in knot securit y was the type of suture material, although there were differences wit h the type of knot. With the Maxon suture, there was significantly dec reased ultimate failure load of all of the arthroscopically tied knots compared with handtied square knots. Knots tied with Ticron were simi lar in strength for both arthroscopically and handtied groups. The sur geon who chooses a monofilament absorbable suture should be aware that a high percentage of knots fail under low load cyclic testing, and th at all of these knots were inferior to handtied square knot controls i n testing to failure.