title: The aetiology of total knee arthroplasty failure influences the improvement in knee function.
abstract: BACKGROUND
  Some indications for revision total knee arthroplasty (TKA), e.g. arthrofibrosis, have been identified to yield inferior results. The aim of this study was to analyse the results of revision TKA according to aetiology of TKA failure.
  
  
  METHODS
  The results of 97 consecutive revision TKA in 97 patients stratified according to the aetiology of primary TKA failure (periprosthetic infection, aseptic loosening, instability and arthrofibrosis), were compared using the Knee Society Score (KSS). The effect of patient age, gender, BMI, American Society of Anesthesiologists (ASA) classification, interval to revision and the occurrence of complications on the outcome were also analysed.
  
  
  RESULTS
  After a mean follow-up of 29 months, the KSS had significantly improved in all patient groups (p < 0.001). The analysis of variance among patient groups depicted no significant differences between preoperative KSS (p = 0.618) and postoperative KSS (p = 0.915), while the magnitude of pre- to postoperative improvement showed significant differences between the groups (p = 0.006). The aetiology of primary TKA failure had an independent influence on pre- to postoperative improvement (p = 0.014). Of the other factors analysed, only the ASA classification had an independent impact on postoperative KSS (p = 0.045).
  
  
  CONCLUSIONS
  The aetiology of TKA failure has an effect on the improvement in knee function from revision TKA. As no difference was observed between patient groups postoperatively, similar clinical results can be expected independent of the aetiology of primary TKA failure.
authors.affiliation: Department of Orthopaedic Surgery, University Hospital Ulm, Oberer Eselsberg 45, 89081, Ulm, Germany. ralf.bieger@uni-ulm.de
authors.forename: Ralf
authors.initials: R
authors.lastname: Bieger
authors.forename: Thomas
authors.initials: T
authors.lastname: Kappe
authors.forename: Christian R
authors.initials: CR
authors.lastname: Fraitzl
authors.forename: Heiko
authors.initials: H
authors.lastname: Reichel
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee; D005260:Female; D005355:Fibrosis / Q000150:complications; D006801:Humans; D007593:Joint Instability / Q000150:complications; D007719:Knee Joint / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011475:Prosthesis Failure / Q000209:etiology*; D016459:Prosthesis-Related Infections / Q000150:complications; D016059:Range of Motion, Articular; D012086:Reoperation