title: Accuracy of a hexapod parallel robot kinematics based external fixator.
abstract: BACKGROUND
  Different hexapod-based external fixators are increasingly used to treat bone deformities and fractures. Accuracy has not been measured sufficiently for all models.
  
  
  METHODS
  An infrared tracking system was applied to measure positioning maneuvers with a motorized Precision Hexapod® fixator, detecting three-dimensional positions of reflective balls mounted in an L-arrangement on the fixator, simulating bone directions. By omitting one dimension of the coordinates, projections were simulated as if measured on standard radiographs. Accuracy was calculated as the absolute difference between targeted and measured positioning values.
  
  
  RESULTS
  In 149 positioning maneuvers, the median values for positioning accuracy of translations and rotations (torsions/angulations) were below 0.3 mm and 0.2° with quartiles ranging from -0.5 mm to 0.5 mm and -1.0° to 0.9°, respectively.
  
  
  CONCLUSIONS
  The experimental setup was found to be precise and reliable. It can be applied to compare different hexapod-based fixators. Accuracy of the investigated hexapod system was high.
authors.affiliation: Berufsgenossenschaftliches Unfallkrankenhaus (Trauma Hospital) Hamburg, Department for Trauma Surgery, Orthopaedics and Sportstraumatology, Hamburg, Germany.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Faschingbauer
authors.affiliation: Berufsgenossenschaftliches Unfallkrankenhaus (Trauma Hospital) Hamburg, Department for Trauma Surgery, Orthopaedics and Sportstraumatology, Hamburg, Germany.
authors.forename: Hinrich J D
authors.initials: HJ
authors.lastname: Heuer
authors.affiliation: Berufsgenossenschaftliches Unfallkrankenhaus (Trauma Hospital) Hamburg, Department for Trauma Surgery, Orthopaedics and Sportstraumatology, Hamburg, Germany.|Berufsgenossenschaftliches Unfallkrankenhaus (Trauma Hospital) Hamburg, Laboratory for Biomechanics, Hamburg, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Seide
authors.affiliation: University Medical Center Schleswig-Holstein, Campus Luebeck, Biomechanics Laboratory, Luebeck, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Wendlandt
authors.affiliation: Berufsgenossenschaftliches Unfallkrankenhaus (Trauma Hospital) Hamburg, Laboratory for Biomechanics, Hamburg, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Münch
authors.affiliation: Berufsgenossenschaftliches Unfallkrankenhaus (Trauma Hospital) Hamburg, Department for Trauma Surgery, Orthopaedics and Sportstraumatology, Hamburg, Germany.|University Medical Center Schleswig-Holstein, Campus Luebeck, Clinic for Musculoskeletal Surgery, Luebeck, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Jürgens
authors.affiliation: University Medical Center Schleswig-Holstein, Campus Luebeck, Clinic for Musculoskeletal Surgery, Luebeck, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Kirchner
mesh_terms: D001696:Biomechanical Phenomena; D004867:Equipment Design; D019544:Equipment Failure Analysis / Q000295:instrumentation* / Q000379:methods; D016267:External Fixators; D021621:Imaging, Three-Dimensional / Q000295:instrumentation* / Q000379:methods; D009038:Motion; D015203:Reproducibility of Results; D065287:Robotic Surgical Procedures / Q000295:instrumentation* / Q000379:methods; D012680:Sensitivity and Specificity
keywords: accuracy; external fixator; hexapod