title: Diabetes does not influence the early outcome of total knee replacement: a prospective study assessing the Oxford knee score, short form 12, and patient satisfaction.
abstract: BACKGROUND
  There is conflicting evidence as to whether diabetes mellitus influences the functional outcome and patient satisfaction after a total knee replacement (TKR). The aim of this study was to assess the effect of diabetes upon the Oxford knee score (OKS), short form (SF)-12, and patient satisfaction after TKR.
  
  
  METHODS
  Prospective pre- and post-operative (one year) OKS and SF-12 scores for 2389 patients undergoing primary TKR were compiled, of which 275 (12%) patients suffered with diabetes. Patient satisfaction was assessed at one year.
  
  
  RESULTS
  Patients with diabetes were more likely to have a greater level of comorbidity (p<0.001), and a worse pre-operative OKS and SF-12 score (p<0.02), compared to those patients without diabetes. Diabetes was not a significant (p>0.41) independent predictor of post-operative OKS or the SF-12 physical score on multivariable analysis. Although, factors more prevalent within the diabetic cohort (heart disease, vascular disease, liver disease, anaemia, depression, back pain, worse pre-operative OKS and SF-12 score) were found to be independent predictors of post-operative OKS and SF-12 physical score. Interestingly, diabetes was associated with a significantly greater improvement in mental wellbeing (SF-12 mental component), which was confirmed on multivariable analysis. Patient satisfaction was not influenced by a concomitant diagnosis of diabetes (p=0.57).
  
  
  CONCLUSIONS
  The outcome of TKR as assessed by the OKS, SF-12, and overall patient satisfaction rates are not influenced by diabetes per se, although factors more prevalent within this population result in a worse post-operative outcome.
  
  
  METHODS
  prospective cohort study, level III.
authors.affiliation: Department of Orthopaedics and Trauma, The Royal Infirmary of Edinburgh, Little France, Edinburgh, EH16 4SA, UK. Electronic address: nickclement@doctors.org.uk.
authors.forename: N D
authors.initials: ND
authors.lastname: Clement
authors.forename: D
authors.initials: D
authors.lastname: MacDonald
authors.forename: R
authors.initials: R
authors.lastname: Burnett
authors.forename: S J
authors.initials: SJ
authors.lastname: Breusch
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects / Q000379:methods*; D016022:Case-Control Studies; D003920:Diabetes Mellitus / Q000175:diagnosis / Q000453:epidemiology* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D020370:Osteoarthritis, Knee / Q000175:diagnosis / Q000453:epidemiology* / Q000601:surgery*; D010147:Pain Measurement; D010149:Postoperative Pain / Q000503:physiopathology; D017060:Patient Satisfaction / Q000706:statistics & numerical data; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011475:Prosthesis Failure; D020127:Recovery of Function; D012016:Reference Values; D018570:Risk Assessment; D012720:Severity of Illness Index; D012737:Sex Factors; D016896:Treatment Outcome
keywords: Diabetes mellitus; Outcome; Satisfaction; Total knee replacement