Surgical knot integrity: Effect of suture type and caliber, and level of residency training

Objective: To evaluate if suture type and caliber or level of residency training affects strength and mode of failure of surgical knots. Design: All residents in an obstetrics and gynecology training program were invited to tie knots on a bench model using 2 calibers (0 and 3-0) of 2 types of surgical suture (polyglactin 910 and polydioxanone). The failure load, mode of failure, and loop lengths of the knots were determined. Setting: University of Texas Southwestern Medical Center, Dallas, Texas. Participants: Physicians enrolled in the University of Texas Southwestern Medical Center Obstetrics and Gynecology residency training program. Results: Seventy-one of 73 residents participated. Knots tied with 0-caliber sutures had a higher mean failure load than those tied with 3-0 caliber sutures. For each type and caliber of suture, there were no differences in failure load between each level of residency training. However, senior residents tied knots with shorter loop lengths and had a lower proportion of knots that unraveled or slipped. Conclusions: Even though there were no differences in failure loads, senior residents tied tighter and more secure knots than their junior counterparts.