title: Medial opening wedge high tibial osteotomy: a prospective cohort study of gait, radiographic, and patient-reported outcomes.
abstract: OBJECTIVE
  To evaluate the effect of medial opening wedge high tibial osteotomy on gait, radiographic, and patient-reported outcomes over a 2-year postoperative period in patients with varus alignment and medial compartment knee osteoarthritis, and to identify significant predictors of outcome.
  
  
  METHODS
  We used an observational cohort study design and prospectively administered 3-dimensional quantitative gait analysis, hip to ankle weight-bearing radiographs, and patient-reported outcomes preoperatively and 6, 12, 18, and 24 months postoperatively. Observed changes with 95% confidence intervals (95% CIs) were calculated. Multivariate linear regression and cluster analysis were used to evaluate associations between patient characteristics and 2-year outcomes in dynamic knee joint load (external knee adduction moment during gait) and Knee Injury and Osteoarthritis Outcome Scores (KOOS).
  
  
  RESULTS
  A total of 126 patients (mean age 47.48 years) were included in the study. Mean changes suggested clinically important improvements in malalignment (change in mechanical axis angle 8.04 degrees [95% CI 7.16 degrees , 8.93 degrees ]), medial compartment load during gait (change in knee adduction moment -1.38 [95% CI -1.53, -1.22] percentage body weight x height), and all KOOS domain scores (change in pain 23.19 [95% CI 19.49, 26.89] KOOS points). A small (13%) increase in knee adduction moment was observed from 6 to 24 months postoperatively. Few preoperative clinical and/or gait characteristics assessed at baseline were significantly associated with 2-year outcomes.
  
  
  CONCLUSIONS
  A medial opening wedge high tibial osteotomy with correction to approximately neutral alignment produces substantial and clinically important changes in dynamic knee joint load and patient-reported measures of pain, function, and quality of life 2 years postoperatively. Changes in knee adduction moment observed in the first 2 years postoperatively should be explored as potential predictors of longer-term success and subgroups of patients with poor outcomes.
authors.affiliation: The Wolf Orthopaedic Biomechanics Laboratory and Fowler Kennedy Sport Medicine Clinic, University of Western Ontario, London, Ontario, Canada. tbirming@uwo.ca
authors.forename: Trevor B
authors.initials: TB
authors.lastname: Birmingham
authors.forename: J Robert
authors.initials: JR
authors.lastname: Giffin
authors.forename: Bert M
authors.initials: BM
authors.lastname: Chesworth
authors.forename: Dianne M
authors.initials: DM
authors.lastname: Bryant
authors.forename: Robert B
authors.initials: RB
authors.lastname: Litchfield
authors.forename: Kevin
authors.initials: K
authors.lastname: Willits
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Jenkyn
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Fowler
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D016000:Cluster Analysis; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D005684:Gait / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery*; D010027:Osteotomy / Q000379:methods*; D017063:Outcome Assessment, Health Care; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011859:Radiography; D013977:Tibia / Q000601:surgery*; D016896:Treatment Outcome