Systematic instruction of arthroscopic knot tying with the ArK Trainer: an objective evaluation tool

Purpose: A Proficiency Formula was introduced as an objective self-evaluation method for evaluating basic arthroscopic knot tying in a laboratory setting. The correlation between the Proficiency Formula and gold standard pass/fail dichotomy was demonstrated, as well as with other popular evaluation tools—task-specific checklist (TSC) and global rating scale (GRS). Method: A step-by-step video tutorial was used to instruct 35 medical students on how to tie an arthroscopic Samsung Medical Center (SMC) knot secured by three half hitches. Participants were video recorded performing arthroscopic knot tying and assessed on their success tying an SMC knot, pass or fail, and through three outcome tools: the Proficiency Formula, GRS and the TSC. Independent samples t test was used to compare the GRS, TSC and Proficiency Formula scores, between those who were passed or failed by the evaluators. Correlation between the measurement scales was tested using Spearman’s rho correlation coefficient. Results: Participants received a mean proficiency score of 195 (140–249). The mean Proficiency score for those that passed was 323 (95 % CI 272–374), for those that failed, 87 (95 % CI 26–148, p < 0.001). We found strong linear correlation between the Proficiency Formula and GRS and TSE (0.83 and 0.78, respectively). Conclusion: The Proficiency Formula has high correlation with gold standard GRS and TSC measurements when used to assess arthroscopic knot tying skills on a model. It has the added advantage of being able to be self-assessed. Level of evidence: II.