title: Total knee arthroplasty after high tibial osteotomy: a registry-based case-control study of 1,036 knees.
abstract: BACKGROUND
  Total knee arthroplasty (TKA) after high tibial osteotomy (HTO) is a technically demanding procedure, and concerns have been raised that previous HTO might compromise the outcome of TKA. The aims of the study were to assess the survivorship of TKA after HTO and to determine whether the survivorship is similar to that of primary TKA without previous HTO.
  
  
  METHODS
  Using the Finnish Arthroplasty Register and the National Hospital Discharge Register, we extracted the data of 1,036 patients [mean age 64.3 years; followup 6.7 years (0-22)] who had undergone TKA after a previous HTO between 1987 and 2008. From this cohort, we calculated the Kaplan-Meier survivorship and compared the survivorship of these cases to that of 4,143 age- and gender-matched patients who had undergone primary TKAs without previous HTO.
  
  
  RESULTS
  In the TKA after HTO group, we found Kaplan-Meier survivorship to be 95.3% at 5 years, 91.8% at 10 years, and 88.4% at 15 years. Those survivorship values were lower than those of patients who had TKA without previous HTO (97.2, 94.5, and 90.6%, respectively) (hazard ratio 1.40; 95% confidence interval 1.09-1.81; p = 0.010).
  
  
  CONCLUSIONS
  Previous studies have described technical difficulties during the TKA procedure after HTO, but they have found no adverse effects on the outcome. Our study supports previous research, and despite the slightly higher revision rate, TKA after HTO provides satisfactory results when compared to routine primary TKAs.
authors.affiliation: Oulu University Hospital, 90029 OYS, Oulu, Finland, tuukka.niinimaki@fimnet.fi.
authors.forename: Tuukka
authors.initials: T
authors.lastname: Niinimäki
authors.forename: Antti
authors.initials: A
authors.lastname: Eskelinen
authors.forename: Pasi
authors.initials: P
authors.lastname: Ohtonen
authors.forename: Ari-Pekka
authors.initials: AP
authors.lastname: Puhto
authors.forename: Bhupinder S
authors.initials: BS
authors.lastname: Mann
authors.forename: Juhana
authors.initials: J
authors.lastname: Leppilahti
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000601:surgery; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D010027:Osteotomy; D011475:Prosthesis Failure; D012042:Registries; D012086:Reoperation; D013977:Tibia / Q000601:surgery; D016896:Treatment Outcome