title: Navigated opening wedge high tibial osteotomy improves intraoperative correction angle compared with conventional method.
abstract: OBJECTIVE
  The correction angle after high tibial osteotomy (HTO) depends on an accurate preoperative planning and an accurate intraoperative technique. We hypothesized that the use of a navigation system in opening wedge HTO would improve the intraoperative target angles in the coronal and sagittal planes.
  
  
  METHODS
  Postoperative femoro-tibial angle (FTA) and tibial posterior slope (TPS) in 28 knees with navigated opening wedge HTO were compared to those in 31 knees with the conventional method. Intraoperative correction angle was determined by the predicted medial opening width in the conventional group, and by the change of hip-knee-ankle angle in the navigated group. We defined lateral unstable knee as the knees with lateral cortex breakage or lateral tibial plateau fracture.
  
  
  RESULTS
  Mean postoperative FTA was higher in the conventional group than in the navigated group (P < 0.037). In the conventional group, 4 lateral unstable knees were corrected to 174.6°. In the navigated group, 5 lateral unstable knees were corrected to 170.3° and no knees showed FTA > 173°. Mean change in TPS was greater in the conventional group than in the navigated group (P = 0.001).
  
  
  CONCLUSIONS
  The navigation system in opening wedge HTO might reduce undercorrection in the knees with lateral cortex breakage or lateral tibial plateau fracture, and provide the better intraoperative FTA and TPS.
  
  
  METHODS
  III.
authors.affiliation: Department of Orthopedic Surgery, Yokohama City University Medical Center, 4-57 Urafune-cho, Minami-ku, Yokohama, 232-0024, Japan. akamatsu@yokohama-cu.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Akamatsu
authors.forename: N
authors.initials: N
authors.lastname: Mitsugi
authors.forename: Y
authors.initials: Y
authors.lastname: Mochida
authors.forename: N
authors.initials: N
authors.lastname: Taki
authors.forename: H
authors.initials: H
authors.lastname: Kobayashi
authors.forename: R
authors.initials: R
authors.lastname: Takeuchi
authors.forename: T
authors.initials: T
authors.lastname: Saito
mesh_terms: D005260:Female; D006801:Humans; D007719:Knee Joint / Q000033:anatomy & histology; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D020370:Osteoarthritis, Knee / Q000601:surgery*; D010027:Osteotomy / Q000379:methods*; D025321:Surgery, Computer-Assisted; D013977:Tibia / Q000601:surgery*