title: Determination of optimal non-invasive patient fixation methods for use in robotic hip replacement surgery--an in vitro study.
abstract: BACKGROUND
  A robotic system for the implantation of a total hip arthroplasty (THA) is currently under development. One of the goals of this system is non-invasive patient fixation, aiding the robotic system by an infrared tracking system. To determine the extent of fixation that can be achieved by non-invasive methods, an in vitro study was performed.
  
  
  METHODS
  In cadaver testing, different non-invasive fixation methods (Arthrex leg holder with tourniquet mechanism; arthroscopic leg holder with disposable foam inserts; gynaecological leg holder; Goepel knee crutch) were evaluated under load in different directions.
  
  
  RESULTS
  Deviation was measured in the range 0.33-18.1 mm with up to 20 N load. The testing showed the pneumatic leg holder system to provide the highest stability, followed by an arthroscopic leg holder system with foam inserts.
  
  
  CONCLUSIONS
  Use of a leg holder with foam inserts produced a stability that should enable tracking of the remaining deviation by the navigation system. We will therefore use this method in our future development of the robotic milling tool.
authors.affiliation: Department of Trauma, Orthopaedics and Reconstructive Surgery, BG Trauma Hospital, Hamburg, Germany. Romeo@apschulz.de
authors.forename: A P
authors.initials: AP
authors.lastname: Schulz
authors.forename: M
authors.initials: M
authors.lastname: Tarabolsi
authors.forename: A
authors.initials: A
authors.lastname: Faber
authors.forename: J
authors.initials: J
authors.lastname: Meiners
authors.forename: M
authors.initials: M
authors.lastname: Kammal
authors.forename: F
authors.initials: F
authors.lastname: Mantwill
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation* / Q000379:methods*; D001182:Arthroscopy / Q000379:methods*; D002102:Cadaver; D004867:Equipment Design; D006801:Humans; D007259:Infrared Rays; D008297:Male; D009068:Movement; D011187:Posture; D017755:Prosthesis Fitting; D012371:Robotics; D025321:Surgery, Computer-Assisted