title: Posterior tibial slope changes after opening- and closing-wedge high tibial osteotomy: a comparative prospective multicenter study.
abstract: BACKGROUND
  Valgus high tibial osteotomy is considered to be an effective treatment for unicompartmental medial osteoarthritis. It is generally admitted that tibial slope increases after open-wedge high tibial osteotomy and decreases after closing-wedge high tibial osteotomy. However, the effects on posterior tibial slope of closing- or opening-wedge osteotomies remain controversial.
  
  
  OBJECTIVE
  We analyzed the modifications of tibial slope after opening- and closing-wedge high tibial osteotomies and compared the results of these two procedures. We hypothesized that there was no difference in postoperative tibial slope between opening and closing-wedge osteotomies.
  
  
  METHODS
  This prospective consecutive nonrandomized multicenter study was conducted between January 2008 and March 2009 and included 321 patients: 205 men and 116 women. A total of 224 patients underwent an opening-wedge high tibial osteotomy and 97 a closing-wedge osteotomy. The mean age was 52 years ± 9 and the mean body mass index was 28kg/m(2) ± 5. The main etiology was primary arthritis. Posterior tibial slope was measured preoperatively and at the last follow-up on a lateral radiograph in relation to the posterior tibial cortex.
  
  
  RESULTS
  In the opening-wedge group, a definite 0.6° increase in tibial slope (P=0.016) was observed. In the closing-wedge group, a definite 0.7° decrease in tibial slope (P=0.02) was found. Fourteen percent of the opening-wedge osteotomies increased tibial slope by 5° or more versus only 2% of the closed-wedge osteotomies (P<0.001). Twelve percent of the closing-wedge high tibial osteotomies led to a decrease of 5° or more of the tibial slope versus 7% of the opening-wedge osteotomies (P<0.02).
  
  
  CONCLUSIONS
  These results confirm what is generally reported in the literature, i.e., an increase in tibial slope in opening-wedge high tibial osteotomy and a decrease in the slope in closing-wedge osteotomies. These tibial slope changes appear to be very limited in this series, less than 1° on average. However, there was a bias since the open-wedge technique was preferred in cases with substantial varus deformity. We emphasize the importance of surgical technique to avoid alteration of the tibial slope, particularly in opening-wedge high tibial osteotomy for which we recommend a release of posterior soft tissue and a complete osteotomy of the posterior cortex of the tibia.
  
  
  METHODS
  III. Prospective consecutive nonrandomized multicenter study.
authors.affiliation: Department of Orthopaedic Surgery and traumatology, Pierre et Marie-Curie Paris VI University, Paris, France. alexandreducat@hotmail.com
authors.forename: A
authors.initials: A
authors.lastname: Ducat
authors.forename: E
authors.initials: E
authors.lastname: Sariali
authors.forename: B
authors.initials: B
authors.lastname: Lebel
authors.forename: P
authors.initials: P
authors.lastname: Mertl
authors.forename: P
authors.initials: P
authors.lastname: Hernigou
authors.forename: X
authors.initials: X
authors.lastname: Flecher
authors.forename: R
authors.initials: R
authors.lastname: Zayni
authors.forename: M
authors.initials: M
authors.lastname: Bonnin
authors.forename: R
authors.initials: R
authors.lastname: Jalil
authors.forename: J
authors.initials: J
authors.lastname: Amzallag
authors.forename: P
authors.initials: P
authors.lastname: Rosset
authors.forename: E
authors.initials: E
authors.lastname: Servien
authors.forename: F
authors.initials: F
authors.lastname: Gaudot
authors.forename: T
authors.initials: T
authors.lastname: Judet
authors.forename: Y
authors.initials: Y
authors.lastname: Catonné
mesh_terms: D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000601:surgery*; D010027:Osteotomy / Q000379:methods*; D011446:Prospective Studies; D011859:Radiography; D013977:Tibia / Q000000981:diagnostic imaging* / Q000601:surgery*; D016896:Treatment Outcome