OPTIMIZING ARTHROSCOPIC KNOTS USING BRAIDED OR MONOFILAMENT SUTURE

Surgeons need to know how the material properties of a suture affect t he security of a surgical knot. The purpose of this study was to compa re the security of some clinically important arthroscopic knots when t ied using a braided multifilament suture and to draw comparisons with results of similar knots tied with monofilament suture. Permanent brai ded polyester suture was used to test 10 knot configurations. Eight of the knots included (1) two types of initial cinching knots followed b y (2) one of four combinations of half-hitches. We also tested the tau t-line hitch locked with half-hitches and the original Revo knot. Each knot was subjected to cyclic loading followed by an ultimate load to failure. Clinical failure was defined as the maximum force that result ed in 3 mm of loop displacement. Force versus displacement data were o btained, and the maximal loop holding capacities were compared statist ically. The Duncan loop with switched-post half-hitches and the Revo k not (Linvatec, Large, FL) showed the highest knot-holding capacities ( mean, 87N and 92N, respectively) when compared with all other configur ations (P<.0001) for braided suture. A similar knot-holding capacity w as described for monofilament suture using the Duncan loop locked with switched-post, reversed-direction half-hitches (mean, 81 N). All knot s without post switching slipped completely at significantly lower loa ds than knots with post switching (monofila ment, P<.001; braided, P<. 0001). When compared with results of knots tied with monofilament sutu re, the braided switched-post configurations had smaller cyclic displa cements (braided, 0.7 mm; monofilament, 1.7 mm). Although the Revo kno t showed good strength for braided suture, it was significantly weaker than other configurations when tied with monofilament suture. Therefo re, it is important to test the knot strength for a given suture mater ial before applying it clinically.