Evaluation of 5 knots and 2 suture materials for arthroscopic rotator cuff repair: very strong sutures can still slip.

Abstract

To compare a standard suture material with a newer material using multiple arthroscopic knot configurations and to evaluate the biomechanical performance of a new sliding-locking knot compared with 4 surgical standards. Controlled laboratory study. Five knots were evaluated (Weston, Tennessee, Duncan, SMC, and the new San Diego knot) using 2 suture materials, No. 2 Ethibond (Ethicon, Somerville, NJ) or No. 2 Fiberwire (Arthrex, Naples, FL). Eight samples were tested for each knot-suture configuration. Samples were pretensioned to 10 N and then loaded from 10 to 45 N for 1,000 cycles. Intact knots were loaded to failure. Fiberwire had significantly higher load-to-failure (276 +/- 24 N) compared with Ethibond (111 +/- 13 N) (P < .001), although there was no significant difference as a function of knot configuration. Of the 40 Fiberwire knots, 3 failed by early slippage during cyclic loading and 8 slipped at very low tension during load-to-failure. None of the Ethibond knots and none of the San Diego knots failed by early slippage. Surface characteristics and suture construction affect the tendency for knot slippage. Surgeons should understand the impact of handling characteristics, frictional properties, and ultimate failure load when selecting suture materials and knots for arthroscopic repair.