Influence of training on reliability of surgical knots

Objectives To determine whether trainees in obstetrics and gynaecology tie adequate surgical knots and to assess whether formal training improves knot tying skills.

Design A comparative study assessing surgical knots before and after tuition.

Population Fourteen trainees in a single obstetrics and gynaecology department.

Setting A basic surgical skills workshop based in a London teaching hospital.

Methods Trainees tied surgical knots around a 120mm jig using 2/0 glycan polymer. Each trainee tied 11 knots before and after a two and a half hour teaching session. Knots were tested using a mechanical testing machine.

Outcome measures Knot strength (N); proportion of knots that were ‘secure’ (defined as those that eventually failed on the testing device by breakage rather than slippage); proportion of knots that were ‘dangerous’ (defined as those with a tensile strength of < 5 N).

Results After tuition, the median knot strength of the whole group was 5.7 N stronger than before instruction (95% CI 4.6–12.3 N). Prior to tuition 13.5% (20/148) knots tied had a tensile strength of < 5 N. This was compared with 3.4% (5/148) after tuition (OR = 0.2, 95% CI 0.1–0.6). Before instruction 55.4% (82/148) of the knots were secure compared with 66.9% (99/148) after tuition (OR = 1.6, 95% CI 1.0–2.7).

Conclusion Knot tying workshops can improve the ability of trainees in obstetrics and gynaecology to tie reef knots.