Variability of surgical knot tying techniques: do we need to standardize?

Knot tying is regarded as a basic surgical skill. However, there is no consensus in the literature on the best/safest technique. The aim of this study was to survey the various techniques used by German surgeons at the different stages of their training.

A knot tying technique was defined based on three criteria, i.e., both thread ends are crossed at the beginning at least two throws tied pulling at the same free end of the thread (standing part) and at least one knot tied changing the standing part. The knot tying techniques of 192 randomly chosen German surgeons practicing in 102 different hospitals were compared against this standard. Besides the status of the participating surgeons, the type of hospital in which they were currently working was recorded.

Of the 192 participants, 69 were consultants, 56 fellows, and 67 residents. Forty-three surgeons (22.4%) worked in primary care centers (PCC), 81 (42.2%) in secondary care centers (SCC), and 68 (35.4%) in tertiary care centers (TCC). 62.5% crossed both thread ends at the beginning, 75.5% performed at least two identical throws keeping the same standing part, and 45.3% changed the standing part. Assessed against the technique defined as standard, 19.8% of all surgeons performed similar surgical knots. Even though consultants crossed both thread ends at the beginning and changed the standing part significantly more often (p = 0.007 and p = 0.031 respectively, Fisher's exact test), the overall rate of identical knots was independent of the status of participants and the type of hospital (p > 0.1, Fisher's exact test).

This explorative study detected a high variability of knot tying techniques among German surgeons. In the absence of any evidence of the superiority of one particular technique, continuing education should focus on the quality of each single knot and perfect the details of the technique used.