title: Computer-assisted navigation is beneficial both in primary and revision surgery with modular rotating-hinge knee arthroplasty.
abstract: OBJECTIVE
  The objective of the present study was to explore the effect of navigation on the reconstruction of the mechanical leg axis, implant positioning and the restoration of the joint line in hinged knee arthroplasty in vivo. We present the first 1- to 3-year clinical and radiological results following computer-navigated implantation of the EnduRo modular rotating-hinge knee arthroplasty system (Aesculap AG, Tuttlingen, Germany) as a primary or revision implant.
  
  
  METHODS
  Thirty-one patients were analysed retrospectively. Indication was revision surgery in 18 patients and complex primary surgery in 13. The clinical and radiological results of 31 patients with a minimum follow-up of 12 months (mean 22.2 ± 6.2 months) were recorded. Age at follow-up was 55.2 ± 9.9 years.
  
  
  RESULTS
  The absolute varus-valgus deviation from the neutral mechanical leg axis was determined at 5.1° ± 5.1° preoperatively and 2.1° ± 1.4° postoperatively. No intraoperative complications or problems with the navigation system were observed. At latest follow-up, no component loosening was detected. Based on the Knee Society Score, a knee score of 64.9 ± 17.7 points and a function score of 67.2 ± 27.3 points were achieved.
  
  
  CONCLUSIONS
  Encouraging short-term clinical and radiological results with the computer-navigated implantation of the modular rotating-hinge EnduRo knee arthroplasty system were found in both primary and revision surgery. The navigation facilitated the reconstruction of the leg axis, implant positioning and the restoration of the joint line.
  
  
  METHODS
  IV.
authors.affiliation: BG Trauma Centre, Eberhard Karls University of Tübingen, Schnarrenbergstraße 95, 72076, Tübingen, Germany.
authors.forename: Björn G
authors.initials: BG
authors.lastname: Ochs
authors.affiliation: BG Trauma Centre, Eberhard Karls University of Tübingen, Schnarrenbergstraße 95, 72076, Tübingen, Germany.
authors.forename: Anna J
authors.initials: AJ
authors.lastname: Schreiner
authors.affiliation: BG Trauma Centre, Eberhard Karls University of Tübingen, Schnarrenbergstraße 95, 72076, Tübingen, Germany.
authors.forename: Peter M
authors.initials: PM
authors.lastname: de Zwart
authors.affiliation: BG Trauma Centre, Eberhard Karls University of Tübingen, Schnarrenbergstraße 95, 72076, Tübingen, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Stöckle
authors.affiliation: BG Trauma Centre, Eberhard Karls University of Tübingen, Schnarrenbergstraße 95, 72076, Tübingen, Germany. ChrGonser@aol.com.
authors.forename: Christoph Emanuel
authors.initials: CE
authors.lastname: Gonser
mesh_terms: D000328:Adult; D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D007720:Knee Prosthesis; D008875:Middle Aged; D011474:Prosthesis Design; D011859:Radiography; D012086:Reoperation; D012189:Retrospective Studies; D013238:Stereotaxic Techniques; D025321:Surgery, Computer-Assisted; D016896:Treatment Outcome
keywords: Computer-assisted surgery; EnduRo; Knee replacement; Navigation; Revision knee arthroplasty; Rotating-hinge knee