title: Navigation evaluation of the pivot-shift phenomenon during double-bundle anterior cruciate ligament reconstruction: is the posterolateral bundle more important?
abstract: OBJECTIVE
  The purpose of this study was to assess the pivot-shift phenomenon during double-bundle anterior cruciate ligament (ACL) reconstruction using a navigation system.
  
  
  METHODS
  Ninety patients who received navigated double-bundle ACL reconstruction were included in this study. The mean age of the patients was 21.9 years. During reconstruction, pivot-shift tests were performed 4 times: before reconstruction, after the posterolateral bundle fixation, after the anteromedial bundle fixation, and after the double-bundle reconstruction. Both tibial internal rotation and anterior translation under the pivot-shift test were measured at each phase by the additional functions of the navigation. The navigation system used in this study was the image-free, which does not require preoperative or intraoperative images, OrthoPilot ACL (version 2.0; B. Braun Aesculap, Tuttlingen, Germany).
  
  
  RESULTS
  Before ACL reconstruction, average (+/- standard deviation) tibial internal rotation and anterior translation under the pivot-shift test were 23.7 degrees +/- 6.1 degrees and 5.2 +/- 2.4 mm. They were significantly decreased to 20.9 degrees +/- 6.4 degrees and 2.3 +/- 1.1 mm after the posterolateral bundle fixation, and also decreased to 22.2 degrees +/- 5.7 degrees and 2.4 +/- 1.1 mm after the anteromedial bundle fixation. There was no significant difference between the groups. After double-bundle reconstruction, they improved to 20.3 degrees +/- 6.3 degrees and 2.0 +/- 1.0 mm.
  
  
  CONCLUSIONS
  Our results indicate that both the posterolateral and the anteromedial bundle similarly control both anterior translation and internal rotation during pivot-shift testing. Double-bundle reconstruction may further improve knee stability.
  
  
  METHODS
  Level II, development of diagnostic criteria on basis of consecutive patients with universally applied reference gold standard.
authors.affiliation: Department of Orthopaedic Surgery, Hirosaki University Graduate School of Medicine, Hirosaki, Japan. yasuyuki@cc.hirosaki-u.ac.jp
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Ishibashi
authors.forename: Eiichi
authors.initials: E
authors.lastname: Tsuda
authors.forename: Yuji
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Harehiko
authors.initials: H
authors.lastname: Tsukada
authors.forename: Satoshi
authors.initials: S
authors.lastname: Toh
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000503:physiopathology / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology / Q000517:prevention & control; D007718:Knee Injuries / Q000503:physiopathology / Q000601:surgery*; D007719:Knee Joint / Q000502:physiology / Q000601:surgery; D008297:Male; D019637:Orthopedic Procedures; D019651:Plastic Surgery Procedures / Q000379:methods; D020127:Recovery of Function; D012399:Rotation; D025321:Surgery, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D055815:Young Adult