Mechanical performance of knots using braided and monofilament absorbable sutures

OBJECTIVE: The study was undertaken to test the integrity of various flat and sliding knots with the use of braided and monofilament absorbable sutures. STUDY DESIGN: There were four study groups, each of which consisted of a single suture type and size, with five different knots. Each combination was tested 10 times for a total of 200 experiments. The suture types used were 0-0 and 2-0 Glycomer 631 (Biosyn) and 0-0 and 2-0 coated Lactomer (Polysorb). Knots tested were the square knots, surgeon's knots, modified granny flat knots, and modified identical and nonidentical sliding knots. Knots were tested to failure with a tensiometer. We compared the proportion of knots becoming untied within each group and the ultimate load required to break tied knots. RESULTS: In the 0-0 and 2-0 Lactomer groups, 90% and 60% of modified identical sliding knots, respectively, became untied, significantly more than all other knots. CONCLUSION: When 0-0 and 2-0 Lactomer sutures were used, modified identical sliding knots should be avoided.