title: The role of computer assisted navigation in revision surgery for failed anterior cruciate ligament reconstruction of the knee: A continuous series of 52 cases.
abstract: BACKGROUND
  The causes of failure of anterior cruciate ligament (ACL) reconstruction mainly involve incorrect tunnel positioning. There is no intraoperative tool allowing the surgeon to test graft biomechanics and to confirm that the new graft is in an optimal position.
  
  
  OBJECTIVE
  Control is improved with computer assisted navigation.
  
  
  METHODS
  In this retrospective study, revision ACL reconstruction was performed with a new autologous graft in a continuous series of 52 failed ACL reconstructions. A computer assisted navigation system was used intraoperatively in all knees. Evaluation with this system confirmed the position of old and new tunnels as well as intraoperative laxity.
  
  
  RESULTS
  Evaluation of tunnel position based on traditional radiological criteria found in the literature significantly underestimated graft biomechanics: 69% of the cases presented with unfavorable graft ansiometry (mean: 13 ± 2.2mm) while the correct position of the tibial tunnel was identified in 64% of cases on radiography and the femoral tunnel in 48%. All new grafts were optimally positioned by the computer assisted navigation system with a mean isometery of 3.2 (± 0.7) mm. Comparative pre- and postoperative evaluation of laxity showed a statistically significant improvement (P < 0.001): preoperative and postoperative Lachman test: 10.5 ± 2 mm and 3 ± 0.5, respectively; global rotational laxity: 24 ± 5° and 37 ± 7° respectively.
  
  
  CONCLUSIONS
  The use of a computer assisted navigation system allows optimal positioning of the graft as well as a predictive assessment of laxity.
authors: Service de chirurgie orthopédique et traumatologie du sport, hôpital sud, CHU de Grenoble, avenue de Kimberley, 38034 Échirolles, France. Electronic address: splaweski@chu-grenoble.fr.
authors: S
authors: S
authors: Plaweski
authors: IM2S Monaco, avenue d'Ostende, 98000 Monaco, France.
authors: B
authors: B
authors: Schlatterer
authors: Service de chirurgie orthopédique et traumatologie du sport, hôpital sud, CHU de Grenoble, avenue de Kimberley, 38034 Échirolles, France.
authors: D
authors: D
authors: Saragaglia
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D012086:Reoperation; D012189:Retrospective Studies; D025321:Surgery, Computer-Assisted / Q000379:methods*; D017211:Treatment Failure; D055815:Young Adult
keywords: ACL reconstruction; ACL revision; Navigation