Global rating systems used in assessing knee arthroplasty outcomes.

Global, aggregated knee rating systems are commonly used to assess patient outcomes following knee arthroplasty. In this study, the authors performed a systematic literature search and found that 17% of the English-language studies addressing primary knee arthroplasty reported on patient outcomes following the procedure using a standardized global rating system. The authors describe, in detail, the rating systems' development and format. This study found 34 different rating systems represented in the literature from 1972 to 1992. Great variability was found in the rating systems' design and utilization. Additionally, these condition-specific, physician-based rating systems did not have documented studies demonstrating their reliability or validity. Future research will need to address the issues of selecting and aggregating outcome measures and of deriving any necessary weighting schemes. The ability of researchers to compare patient outcomes across studies will be enhanced when there is consistency in reported outcome measures.