title: Navigation forces during wrist arthroscopy: assessment of expert levels.
abstract: OBJECTIVE
  To facilitate effective and efficient training in skills laboratory, objective metrics can be used. Forces exerted on the tissues can be a measure of safe tissue manipulation. To provide feedback during training, expert threshold levels need to be determined. The purpose of this study was to define the magnitude and the direction of navigation forces used during arthroscopic inspection of the wrist.
  
  
  METHODS
  We developed a set-up to mount a cadaver wrist to a 3D force platform that allowed measurement of the forces exerted on the wrist. Six experts in wrist arthroscopy performed two tasks: (1) Introduction of the camera and visualization of the hook. (2) Navigation through the wrist with visualization of five anatomic structures. The magnitude (Fabs) and direction of force were recorded, with the direction defined as α being the angle in the vertical plane and β being the angle in the horizontal plane. The 10th-90th percentile of the data were used to set threshold levels for training.
  
  
  RESULTS
  The results show distinct force patterns for each of the anatomic landmarks. Median Fabs of the navigation task is 3.8 N (1.8-7.3), α is 3.60 (-54-44) and β is 260 (0-72).
  
  
  CONCLUSIONS
  Unique expert data on navigation forces during wrist arthroscopy were determined. The defined maximum allowable navigation force of 7.3 N (90th percentile) can be used in providing feedback on performance during skills training. The clinical value is that this study contributes to objective assessment of skills levels.
authors.affiliation: Department of Plastic, Reconstructive and Hand Surgery, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, Netherlands. m.c.obdeijn@amc.uva.nl.
authors.forename: Miryam C
authors.initials: MC
authors.lastname: Obdeijn
authors.affiliation: Department of Biomechanical Engineering, Delft University of Technology, Delft, Netherlands.
authors.forename: Tim
authors.initials: T
authors.lastname: Horeman
authors.affiliation: Department of Technical Medicine, MIRA Institute for Biomedical Technology and Technical Medicine Enschede, University of Twente, Enschede, Netherlands.
authors.forename: Lisanne L
authors.initials: LL
authors.lastname: de Boer
authors.affiliation: Department of Technical Medicine, MIRA Institute for Biomedical Technology and Technical Medicine Enschede, University of Twente, Enschede, Netherlands.
authors.forename: Sophie J
authors.initials: SJ
authors.lastname: van Baalen
authors.affiliation: Department of Hand Surgery, Strasbourg University Hospitals, Illkirch, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Liverneaux
authors.affiliation: Department of Biomechanical Engineering, Delft University of Technology, Delft, Netherlands.|Department of Orthopedic Surgery, Orthopedic Research Center Amsterdam, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands.
authors.forename: Gabrielle J M
authors.initials: GJ
authors.lastname: Tuijthof
mesh_terms: D000328:Adult; D001182:Arthroscopy / Q000193:education / Q000379:methods / Q000592:standards*; D002102:Cadaver; D002983:Clinical Competence; D006801:Humans; D008875:Middle Aged; D000072161:Orthopedic Surgeons; D011312:Pressure; D012016:Reference Values; D066231:Surgeons; D013518:Surgery, Plastic; D014955:Wrist Joint / Q000601:surgery*
keywords: Education; Experts; Forces; Skills assessment; Wrist arthroscopy