title: Component sizing in total knee arthroplasty: patient-specific guides vs. computer-assisted navigation.
abstract: BACKGROUND
  Patient-specific guides (PSG) and computer-assisted navigation (CAN) are technologies that have been developed to improve the accuracy and reproducibility of total knee arthroplasty (TKA). The purpose of this study is to compare the methodology by which a PSG system and an intraoperative navigation system (CAN) perform an anatomical registration and correctly predict femoral component size in TKA.
  
  
  METHODS
  One hundred and eleven PSG TKA were performed, 30 of which were concurrently evaluated with CAN. PSG-predicted and CAN-predicted femoral component size were compared with the actual component selection. The process by which PSG and CAN determines component sizing was evaluated.
  
  
  RESULTS
  The PSG system was both more accurate and more precise than the CAN navigation system in predicting femoral component size in TKA.
  
  
  CONCLUSIONS
  In this study, the surgeon's final component selection was more likely to be in accordance with the PSG rather than the CAN sizing algorithm. This study suggests that intraoperative surface registration may not be as accurate as preoperative three-dimensional magnetic resonance imaging reconstructions for establishing optimal femoral component sizing.
authors.affiliation: Department of Orthopedic Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Yaffe
authors.forename: Anay
authors.initials: A
authors.lastname: Patel
authors.forename: Brett W
authors.initials: BW
authors.lastname: Mc Coy
authors.forename: Michael
authors.initials: M
authors.lastname: Luo
authors.forename: Max
authors.initials: M
authors.lastname: Cayo
authors.forename: Raju
authors.initials: R
authors.lastname: Ghate
authors.forename: S David
authors.initials: SD
authors.lastname: Stulberg
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods / Q000706:statistics & numerical data*; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D007593:Joint Instability / Q000453:epidemiology* / Q000601:surgery*; D007719:Knee Joint / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D017755:Prosthesis Fitting / Q000379:methods / Q000706:statistics & numerical data*; D018570:Risk Assessment; D025321:Surgery, Computer-Assisted / Q000379:methods / Q000706:statistics & numerical data*; D016896:Treatment Outcome