Construct validity testing of the Arthroscopic Knot Trainer (ArK)

Purpose: This study introduced a novel simulator called the Arthroscopic Knot Trainer (ArK) and reports preliminary evidence to support its construct validity. To our knowledge, the ArK is the first non-anatomical tissue reduction simulator designed to meet learning objectives specific for developing knot-tying skills. Materials and methods: A step-by-step instructional video was used to teach orthopaedic residents how to tie an arthroscopic SMC knot. Residents were video recorded to assess time of completion, number of knots tied in 10 min and re-assessed 6 months later. Subjects were surveyed for content evidence after using the ArK. Data were analysed by paired t test and independent sample t test in order to compare the mean time to tie knots from test at baseline to retest at 6 months and the between group mean time, respectively. Results: Content evidence supports the ArK trainer as appropriate for teaching and assessing arthroscopic knot-tying skills. Relation to other variables evidence supports the ArK trainer model whether stratified by year of training or by self-reported experience; time required for knot tying was inversely correlated with experience in tying arthroscopic knots. Internal structure evidence was supported with similar findings at retesting. Conclusions: There are three sources of evidence supporting the construct validity of the ArK as a simulator for arthroscopic knot tying: content, relationship to other variable and internal structure evidence. The ArK is easy to use and has the capacity to distinguish between groups with different skill levels. Level of evidence: II.