Tying a loop-to-strand suture: Is it safe?

Objective This study was undertaken to evaluate the integrity of the loop-to-strand knot when tied with square and nonidentical sliding knots. Study design The synthetic absorbable monofilament suture poliglecaprone 25 in 0 and 2-0 suture gauges was used in this experiment. For each suture gauge, 3 groups of knots were tested: (1) single strand-to-single strand, flat square knot, (2) loop-to-single strand, flat square knot, and (3) loop-to-single strand, nonidentical sliding knot. All knots were tied with 6 throws. The proportion of knots becoming untied was compared among the 3 groups for each suture gauge. Ultimate load required to untie or break knots within each group was also evaluated. Results The loop-to-strand knot performed well in both suture gauges tested as long as it was tied with a flat square knot. The loop-to-strand knot tied with a nonidentical sliding knot had an unacceptably high failure rate. Conclusion The loop-to-strand termination of a continuous suture may be acceptable when tied with a 6-throw flat square knot but not acceptable if tied with sliding knots.