title: Navigation of total knee arthroplasty: rotation of components and clinical results in a prospectively randomized study.
abstract: BACKGROUND
  Navigation was introduced into total knee arthroplasty (TKA) to improve accuracy of component position, function and survival of implants. This study was designed to assess the outcome of navigated TKA in comparison with conventional implantation with the focus on rotational component position and clinical mid-term results.
  
  
  METHODS
  In a prospectively randomized single-blinded approach, 90 patients with primary gonarthrosis were assigned to three different groups. Thirty patients each were assigned to NexGen LPS without and with navigation (groups 1 and 2), and 30 patients to navigation with the Stryker Scorpio PS (group 3). The navigation system used was the imageless Stryker KneeTrac, version 1.0. Clinical outcome was assessed by a blinded observer applying the Knee Society Score (KSS) and a visual analogue scale (VAS) for pain. CT scans and radiographs were conducted prior to and 12 weeks after index surgery.
  
  
  RESULTS
  Seventy-nine patients were available for clinical evaluation at 3 ± 0.4 years follow-up. Four implants had to be revised for early loosening or infection (4.4%). Four patients had died and three patients were not able to follow the invitation for clinical assessment. Functional results in the KSS were significantly lower after navigated TKA. Operation time and incisions with navigation were significantly longer. Significantly less radiological outliers with navigation were found for coronal alignment of the femur, only.
  
  
  CONCLUSIONS
  In this series, no beneficial effect for navigation in TKA could be shown assessing clinical data, as functional results in the presented series seemed to be lower after first generation navigated TKA. The clinical mid- to long-term value of navigation remains to be evaluated in larger patient series or meta-analyses at longer follow-up.
  
  
  BACKGROUND
  DRKS 00000430.
authors.affiliation: Department of Orthopedics and Rheumatology, University Hospital Marburg, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Schmitt
authors.forename: Carsten
authors.initials: C
authors.lastname: Hauk
authors.forename: Heino
authors.initials: H
authors.lastname: Kienapfel
authors.forename: Michael
authors.initials: M
authors.lastname: Pfeiffer
authors.forename: Turgay
authors.initials: T
authors.lastname: Efe
authors.forename: Susanne
authors.initials: S
authors.lastname: Fuchs-Winkelmann
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Heyse
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation / Q000379:methods*; D004868:Equipment Failure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D011446:Prospective Studies; D019736:Prostheses and Implants / Q000592:standards*; D019919:Prosthesis Implantation / Q000295:instrumentation / Q000379:methods*; D012399:Rotation / Q000009:adverse effects; D016037:Single-Blind Method; D025321:Surgery, Computer-Assisted / Q000379:methods*