Functional Rating for Knee Arthroplasty: Comparison of Three Scoring Systems

Abstract

This study evaluated the reliability of three rating systems for total knee arthroplasty. Twenty-nine patients were assessed by six observers with the American Knee Society Score, the British Orthopaedic Association Score, and the Oxford 12-item questionnaire. The inter- and intraobserver variations were calculated for the American Knee Society Score and the British Orthopaedic Association Score, as was the reproducibility of the Oxford 1 2-item questionnaire. Components of the scores were evaluated for agreement using Kappa statistics. The British Orthopaedic Association Score had smaller interobserver variation compared to the American Knee Society Score, and the greatest reproducibility of the three systems. This was attributed to the equal weighting of its component variables. The Oxford 1 2-item questionnaire, a self-administered questionnaire that eliminates interobserver error, emerged as the most reliable system. Observer experience affected the reliability of the American Knee Society Score and the British Orthopaedic Association Score. Subjective variables were more reliable and reproducible than the objective components.

The association between radiographic severity and pre-operative function in patients undergoing primary knee replacement for osteoarthritis

“…While our patient demographic is similar to that of other arthroplasty centres with respect to age [17,51] and obesity rates [52,53], the percentage of women who underwent knee replacement was marginally higher than that of other centres [17,51]. We recognise the limitations of using the International Knee Society Score (IKS) in terms of potential observer bias associated with a scoring system that is partly completed by the health care provider [54]. We attempted to avoid observer bias by assessing pain and function with the IKS components that are administered to patients for self assessment.…”

Translation and validation of the Dutch version of the Oxford 12-item knee questionnaire for knee arthroplasty

“…Reliability is defined as the ability of a test to "yield the same results on repeated trials under the same conditions" (Liow et al 2003). To determine the test-retest reliability, a second questionnaire was given to a random sample of 26 patients who were scheduled for total knee arthroplasty.…”

“…The WOMAC is a commonly used diseaseand site-specific questionnaire, but it was not developed specifically to evaluate functional outcome of TKA (Bellamy et al 1988). The 12-item knee questionnaire has been shown to be reliable and the most appropriate for the assessment of outcome after total knee arthroplasty (Dunbar et al 2000, 2001, Davies 2002, Liow et al 2003. A validated Dutch version of the 12-item knee questionnaire would therefore be of value.…”

“…Since then, it has proven to be an effective outcome questionnaire and is widely used (Dunbar et al 2000, Liow et al 2003, Padua et al 2003. Despite the positive psychometric properties for the Total Knee Arthroplasty (TKA) population, the 12-item knee questionnaire has only been translated into a few languages and subsequently validated in only two cases: Swedish and Italian (Dunbar et al 2000, Padua et al 2003.…”

“…Davies (2002) recently performed a review of all knee-specific questionnaires, concluding that the 12-item knee questionnaire, the 36-item Short-Form health survey (SF-36) and the WOMAC were the most appropriate for the assessment of outcome after total knee arthroplasty. Liow et al (2003) recently compared studies of different functional rating systems for TKA and the 12-item knee questionnaire emerged as the most reliable, since it eliminates interobserver errors.…”