PURPOSE: Surgical knot-tying requires careful selection of the appropriate technique for optimal outcomes
however, evidence is lacking about the common ligation techniques combining square and slip knots (combination knots). This study investigates the strength of a combination knot, compared with other techniques. METHODS: In this observational cohort study, we assessed the strengths of square, slip-granny, slip-reef, and combination knots using absorbable monofilament sutures, and compared them using ANOVA and a multilevel linear regression analysis. We also assessed the correlation between the number of throws and knot strength using Spearman's correlation analysis. RESULTS: Among 80 ligatures, ANOVA indicated significant differences in knot strength among the techniques (p <
0.01). Multilevel linear regression showed that a combination knot was stronger than a slip knot (p <
0.01) and comparable to a square knot (p = 0.0721). Secondary analysis indicated that for combination knots, five throws could achieve sufficient knot strength. CONCLUSION: Combination knots are as strong as square knots and stronger than slip knots, and thus present a reasonable option for surgical ligation.