title: Predictive values of WOMAC, KOOS, and SF-12 score for knee arthroplasty: data from the OAI.
abstract: OBJECTIVE
  A number of validated scores are available to monitor clinical outcome after knee arthroplasty. The current study examines whether WOMAC, KOOS, or SF-12 scores have a predictive value to identify patients that require total knee arthroplasty within 1 year.
  
  
  METHODS
  The Osteoarthritis Initiative includes 4684 patients in two groups: incidence subcohort (Group A, n = 3284) and progression subcohort (Group B, n = 1400). A total of 278 patients reached the endpoint "unilateral knee replacement" (Group A = 96; Group B = 182). WOMAC, KOOS, and SF-12 scores at the maximum of 12 months prior to surgery were used to analyse predictive values. ROC analysis and the diagnostic accuracy for these scores were reported.
  
  
  RESULTS
  Group A: WOMAC and KOOS score as well as the "physical component summary" of SF-12 showed an area under the curve (AUC) between 0.8 and 0.9 (high diagnostic evidence) to predict total knee replacement. The KOOS "symptoms" (0.67) and SF12 "function" (0.79) showed lower values. The KOOS QoL score showed the highest predictive value with an AUC of 0.84 (CI 95% 0.77-0.91, p < 0.001) resulting in a sensitivity of 0.88 and a specificity of 0.72. Similar numbers were achieved by the total WOMAC score with an AUC of 0.85 (CI 95% 0.82-0.88, p < 0.001) resulting in a sensitivity of 0.77 and a specificity of 0.82. The SF-12 physical component score had an AUC of 0.83 (CI 95% 0.79-0.87, p < 0.001) resulting in a sensitivity of 0.87 and a specificity of 0.68. Different combinations of scores increase the positive likelihood ratio (up to 18) and specificity (up to 0.97). Group B scores showed lower AUCs, sensitivities and specificities.
  
  
  CONCLUSIONS
  Combinations of WOMAC, KOOS, or SF-12 scores accurately predict patients that require knee arthroplasty within 1 year. In addition to other clinical parameters (physical examination, radiographs), they can guide patient and surgeon during the treatment of arthritis of the knee.
  
  
  METHODS
  II.
authors.affiliation: Hospital for Special Surgery, 535 East 70th Street, New York, NY, 10021, USA. martin.faschingbauer@outlook.com.|Department of Orthopedic Surgery, RKU, University of Ulm, Oberer Eselsberg 45, 89081, Ulm, Germany. martin.faschingbauer@outlook.com.
authors.forename: M
authors.initials: M
authors.lastname: Faschingbauer
authors.affiliation: Hospital for Special Surgery, 535 East 70th Street, New York, NY, 10021, USA.
authors.forename: M
authors.initials: M
authors.lastname: Kasparek
authors.affiliation: Hospital for Special Surgery, 535 East 70th Street, New York, NY, 10021, USA.
authors.forename: P
authors.initials: P
authors.lastname: Schadler
authors.affiliation: Department of Orthopedic Surgery, RKU, University of Ulm, Oberer Eselsberg 45, 89081, Ulm, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Trubrich
authors.affiliation: Department of Orthopedic Surgery, RKU, University of Ulm, Oberer Eselsberg 45, 89081, Ulm, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Urlaub
authors.affiliation: Hospital for Special Surgery, 535 East 70th Street, New York, NY, 10021, USA.
authors.forename: F
authors.initials: F
authors.lastname: Boettner
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D011379:Prognosis; D016896:Treatment Outcome
keywords: KOOS; Knee arthroplasty; OAI; Predictive value; SF-12; WOMAC