Optimization of stacked half-hitch knots for arthroscopic surgery

Purpose: This study was conducted to determine the optimal configuration of stacked half-hitch knots that would give the maximum knot-holding capacity (KHC). Type of Study: Mechanical testing study. Methods: The 2 types of su ture materials tested were No. I PDS II monofilament and No. 2 Ethibond bra ided (Ethicon, Somerville, NJ) because these are the 2 most commonly used s utures in arthroscopic surgery. Twelve configurations of stacked half-hitch knots including 2 versions of the Revo knot were tested. Knots were tied b etween 2 steel hooks 7 mm apart on a manual knot-testing machine. The steel hooks were spread apart to break the knot and the KHC was determined by th e peak load recorded on the digital force transducer. Maximum KHC was achie ved for No. 1 PDS II sutures by locking the knot with 2 RHAPs (reversing ha lf-hitch on alternate post) and, for No. 2 Ethibond sutures, by locking the knot with 3 RHAPs. Because of the possibility of PDS II sutures unraveling , it is recommended for both No. 1 PDS II and No. 2 Ethibond sutures, that all stacked half-hitches be locked with 3 RHAPs. By adding I RHAP to the Re vo knot, failure by slippage can be eliminated. Results: The recommended kn ots tied with braided No. 2 Ethibond sutures were 1.5 times stronger than k nots tied with No. 1 PDS II sutures. Although there was variability in the KHC of the recommended knots tied by different surgeons using different kno t tiers, the greatest difference in the mean KHC was less than 10%. Conclus ions: Stacked half-hitch knots locked with 3 RHAPs are unlikely to fail by slippage.