Comparison of knot-tying proficiency and knot characteristics for square and reversing half hitch alternating-post surgical knots in a simulated deep body cavity among notice medical students.

Abstract

Proficiency-based knot-tying curricula have been developed for square knots for medical students, but, to our knowledge, no such curriculum exists for the reverse half hitch alternating-post (RHAP) knot. We aimed to compare medical students' knot-tying proficiency, knot-tying self-confidence and final knot characteristics for RHAP and square knots in a simulated deep body cavity. We performed a within-subject prospective crossover study of novice medical students who received 30 minutes of training in tying both RHAP and square knots. Participant performance was assessed via a knot-tying checklist, and knot configuration, tensile strength, tightness (loop circumference) and mechanism of failure were also assessed. Participants' self-reported confidence in knot tying was captured. Twenty-one students participated in the study. Mean scores on the knot-tying checklist were significantly higher for RHAP knots than for square knots (6.9 [standard deviation (SD) 2.1] v. 5.2 [SD 2.3], p < 0.01), and RHAP knots were significantly tighter than square knots (46.8 mm [SD 0.4 mm] v. 49.3 mm [SD 0.7 mm], p < 0.05). There were no differences between RHAP and square knots in correct knot configuration, breaking strength or mechanism of failure. Reverse half hitch alternating-post knots were easier to tie within a deep-body cavity, whereas square knots were easier to learn. Novice medical students were more proficient in tying RHAP knots than square knots in a simulated deep body cavity. Students were able to construct RHAP knots more securely and reported increased confidence in tying RHAP knots at depth compared to square knots.