title: Differences between experts and trainees in the motion pattern of the dominant upper limb during intracorporeal endoscopic knotting.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Surgery and Surgical Skills Unit, Ninewells Hospital and Medical School, Dundee, Scotland.
authors.forename: T A
authors.initials: TA
authors.lastname: Emam
authors.forename: G B
authors.initials: GB
authors.lastname: Hanna
authors.forename: C
authors.initials: C
authors.lastname: Kimber
authors.forename: A
authors.initials: A
authors.lastname: Cuschieri
mesh_terms: D000328:Adult; D001132:Arm / Q000502:physiology; D001696:Biomechanical Phenomena; D002983:Clinical Competence; D004724:Endoscopy; D013502:General Surgery; D006801:Humans; D010535:Laparoscopy; D008875:Middle Aged; D009048:Motor Skills; D009068:Movement