title: Long-term outcome of total knee replacement: does obesity matter?
abstract: BACKGROUND
  Although arthritic complications are common in the obese, many surgeons are reluctant to perform joint replacements in this population. We compared outcomes of total knee arthroplasties (TKAs) in normal weight and obese patients.
  
  
  METHODS
  30 TKAs in 21 obese patients with BMI 30-49 (Group A--mainly mildly and moderately obese) were compared to a matched group of 53 TKAs in 41 non-obese patients with BMI 16-29.9 (Group B). Outcome measures included the Knee Society Score (a composite of clinical and functional parameters), radiographic results, and the need for revision or reoperation.
  
  
  RESULTS
  Median follow-up was 11.3 years; no patients were lost to follow-up during this time. The Knee Society Score rose 92 points in Group A to a final score of 184, and 95 points in Group B to a score of 193. There was no statistical difference in Groups A and B between the improvement in scores or the final score achieved. Osteolysis rates were not significantly different between the 2 groups (5% vs 13%), nor were radiolucency rates (0% vs 9.7%). Median alignment was also similar in both groups (8.1 degrees vs 8.0 degrees valgus). 13.3% of Group A required reoperation while none required revision, and 13.2% of Group B required reoperation with 3.8% requiring revision. Survival rates were similar in both groups (71.4% vs 61.5%).
  
  
  CONCLUSIONS
  Moderate obesity does not affect the clinical and radiologic outcome of TKA. However, TKA results in improved mobility, enhancing the success of subsequent weight loss therapy.
authors.affiliation: Department of Orthopedic Surgery, University of Southern California, Los Angeles, CA 90033, USA.
authors.forename: Nahid
authors.initials: N
authors.lastname: Hamoui
authors.forename: Stephen
authors.initials: S
authors.lastname: Kantor
authors.forename: Kelly
authors.initials: K
authors.lastname: Vince
authors.forename: Peter F
authors.initials: PF
authors.lastname: Crookes
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001168:Arthritis / Q000453:epidemiology / Q000601:surgery*; D019645:Arthroplasty, Replacement, Knee; D015897:Comorbidity; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000453:epidemiology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology*; D016896:Treatment Outcome