title: A marker placement laser device for improving repeatability in 3D-foot motion analysis.
abstract: BACKGROUND
  In 3D gait analysis, the repeated positioning of markers is associated with a high error rate, particularly when using a complex foot model with many markers. Therefore, a marker placement laser device was developed that ensures a reliable repositioning of markers. We report the development and reliability of this device for the foot at different tape conditions.
  
  
  METHODS
  In 38 subjects, markers were placed at the foot according to the Heidelberg foot measurement method. Subjects were tested barefoot and barefoot with three different tape conditions. For all conditions, a static standing trial was captured. We analyzed differences in distances between markers and the intra-class correlation coefficients (ICC).
  
  
  RESULTS
  Small differences between the conditions (0.03-3.28 mm) and excellent ICCs (0.91-0.97 mm) were found for all parameters.
  
  
  CONCLUSIONS
  The laser marker placement device appeared to be a reliable method to place markers on a tape at previously palpated positions and ensures an exact position. The device could find a wide application in different clinical research fields.
authors.affiliation: Clinic for Orthopedics and Trauma Surgery, Center for Orthopedics, Trauma Surgery and Spinal Cord Injury, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Kalkum
authors.affiliation: Clinic for Orthopedics and Trauma Surgery, Center for Orthopedics, Trauma Surgery and Spinal Cord Injury, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: van Drongelen
authors.affiliation: Clinic for Orthopedics and Trauma Surgery, Center for Orthopedics, Trauma Surgery and Spinal Cord Injury, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Mussler
authors.affiliation: Clinic for Orthopedics and Trauma Surgery, Center for Orthopedics, Trauma Surgery and Spinal Cord Injury, Heidelberg University Hospital, Heidelberg, Germany.
authors.forename: Sebastian I
authors.initials: SI
authors.lastname: Wolf
authors.affiliation: Clinic for Orthopedics and Trauma Surgery, Center for Orthopedics, Trauma Surgery and Spinal Cord Injury, Heidelberg University Hospital, Heidelberg, Germany. Electronic address: benita@kuni.org.
authors.forename: Benita
authors.initials: B
authors.lastname: Kuni
mesh_terms: D016512:Ankle Injuries / Q000517:prevention & control; D055052:Athletic Tape; D001696:Biomechanical Phenomena; D005260:Female; D057918:Fiducial Markers; D005528:Foot / Q000502:physiology*; D005684:Gait / Q000502:physiology*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation* / Q000379:methods; D007834:Lasers; D008297:Male; D015203:Reproducibility of Results
keywords: Foot model; Laser device; Marker replacement error; Repeatability; Tape