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Article
Validity and Responsiveness of the Knee Injury and Osteoarthritis Outcome Score: A Comparative Study Among Total Knee Replacement Patients
University of Massachusetts Medical School Faculty Publications
  • Barbara L. Gandek, University of Massachusetts Medical School
  • John E. Ware, Jr., University of Massachusetts Medical School
UMMS Affiliation
Department of Quantitative Health Sciences
Date
6-1-2017
Document Type
Article
Abstract

OBJECTIVE: To evaluate validity and responsiveness of the Knee Injury and Osteoarthritis Outcome Score (KOOS) in relation to other patient-reported outcome measures before and after total knee replacement (TKR).

METHODS: Pre-TKR and 6-month post-TKR data from 1,143 patients in a US joint replacement cohort were used to compare the KOOS, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the SF-36 Health Survey (SF-36). Validity was evaluated with multiple methods, including correlations of pre-TKR scale scores and analysis of variance models that used pre-TKR data to compare the relative validity of scales in discriminating between groups differing in assistive walking device use and number of comorbid conditions. Validity was also evaluated by using post-TKR minus pre-TKR change scores to assess relative validity of scales in discriminating between groups rating themselves as better, same, or worse (BSW) in their capability to do activities at 6 months. Responsiveness also was described using effect sizes and standardized response means.

RESULTS: In support of convergent and discriminant validity, KOOS scale scores were worse for patients using an assistive device but only declined weakly with increasing comorbid conditions. While all knee-specific scales discriminated between BSW groups, the KOOS quality of life (QOL) scale was significantly better (P < 0.05) than all measures except the SF-36 physical component summary. KOOS QOL also had the highest effect size, while SF-36 measures had lower effect sizes and standardized response means. KOOS pain and symptoms scales discriminated better than WOMAC pain and stiffness scales among BSW groups.

CONCLUSION: KOOS scales were valid and responsive in this cohort of US TKR patients. KOOS QOL performed particularly well in capturing aggregate knee-specific outcomes.

Rights and Permissions
Citation: Arthritis Care Res (Hoboken). 2017 Jun;69(6):817-825. doi: 10.1002/acr.23193. Epub 2017 May 8. Link to article on publisher's site
Related Resources
Link to Article in PubMed
PubMed ID
28085998
Citation Information
Barbara L. Gandek and John E. Ware. "Validity and Responsiveness of the Knee Injury and Osteoarthritis Outcome Score: A Comparative Study Among Total Knee Replacement Patients" (2017) ISSN: 2151-464X (Linking)
Available at: http://works.bepress.com/john_ware/226/