Differences between Experts and Trainees in the Motion Pattern of the Dominant Upper Limb during Intracorporeal Endoscopic Knotting

BACKGROUND: Very little research has been carried out on the ergonomics of surgeon-instrument interface. The aim of this study is to investigate the effect of experience on the motion pattern of the dominant upper limb during endoscopic intracorporeal knot tying. METHODS: Two groups of 5 surgeons (expert consultants and higher surgical trainees) tied 360 surgeon's knots inside an endoscopic trainer in a random sequence. Motion analysis at the elbow and shoulder joints of the dominant upper limb was carried out using 3-dimensional kinemetrix system. Each knot was distracted using a tensiometer. The endpoints were the execution time, knot quality score, angular velocity and range of movement. Kruskal-Wallis one-way analysis of variance and Mann-Whitney U test were used for analysis. RESULTS: The expert group had a better knot quality score (p < 0.005) and shorter execution time (p < 0.0001) than beginners. Motion analysis at the shoulder joint showed that experts had a higher angular velocity (p < 0.05) and a wider range of movement with more adduction (p < 0.01) compared to beginners. No significant differences were found at the elbow. CONCLUSION: The better task performance by expert surgeons is associated with controlled rapid manipulations and a wider range of movement at the shoulder joint of the dominant upper limb.