title: A technical innovation for improving identification of the trackers by the LED cameras in navigation-assisted total knee arthroplasty.
abstract: OBJECTIVE
  To reduce the operating time in computer-assisted navigated total knee replacement (TKR), by improving communication between the infrared camera and the trackers placed on the patient.
  
  
  METHODS
  The innovation involves placing a routinely used laser pointer on top of the camera, so that the infrared cameras focus precisely on the trackers located on the knee to be operated on. A prospective randomized study was performed involving 40 patients divided into two groups, A and B. Both groups underwent navigated TKR, but for group B patients a laser pointer was used to improve the targeting capabilities of the cameras.
  
  
  RESULTS
  Without the laser pointer, the camera had to move a mean 9.2 times in order to identify the trackers. With the introduction of the laser pointer, this was reduced to 0.9 times. Accordingly, the additional mean time required without the laser pointer was 11.6 minutes.
  
  
  CONCLUSIONS
  Time delays are a major problem in computer-assisted surgery, and our technical suggestion can contribute towards reducing the delays associated with this particular application.
authors.affiliation: Princess Elizabeth Orthopaedic Centre, Knee Unit, Royal Devon and Exeter Hospital, Exeter, United Kingdom. darmanis@otenet.gr
authors.forename: Spyridon
authors.initials: S
authors.lastname: Darmanis
authors.forename: Andrew
authors.initials: A
authors.lastname: Toms
authors.forename: Robert
authors.initials: R
authors.lastname: Durman
authors.forename: Donna
authors.initials: D
authors.lastname: Moore
authors.forename: Keith
authors.initials: K
authors.lastname: Eyres
mesh_terms: D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D004867:Equipment Design; D006801:Humans; D007834:Lasers; D020370:Osteoarthritis, Knee / Q000601:surgery; D010865:Pilot Projects; D025321:Surgery, Computer-Assisted / Q000295:instrumentation*; D016896:Treatment Outcome; D014741:Video Recording / Q000379:methods*