The Oxford Knee Score (OKS)
The Oxford Knee Score (OKS) is a patient-reported outcome measure (PROM) developed in 1996 to specifically evaluate total knee replacement outcomes. Since then, its scope has broadened to include use in other joint disorders and in surgical treatment, not limited to arthroplasty. The Oxford Knee (and Hip) Scores have undergone rigorous assessments of reliability, validity, and responsiveness in many studies . They have been used in trials and audits, and have played a key role in the national joint replacement registries, including those in England, New Zealand, and Sweden .
The Oxford Knee Score continues to enjoy widespread popularity as a PRO measure, but unfortunately, its popularity has made it a victim of its own success. The extensive use of this measure resulted in many modified versions being utilized for different purposes, which inevitably led to confusion in some areas. In 2007, the original developers of the tool released a statement to help address this issue and sought to clarify the correct usage and scoring methodology of the Oxford Knee Score.
The OKS questionnaire consists of 12 questions that cover the function and pain of the knee. Each question is scored from 0 to 4 (0 being the worst outcome and 4 being the best). The overall score is the sum of all items and can range from 0 to 48, with higher scores corresponding to better outcomes. This simple scoring process is the one that the authors recommend be utilized.
The Oxford Knee Score is a well-regarded PRO measure, proven to be valid and sensitive to clinically important changes over time, specifically in patients undergoing a total joint replacement. The survey is also short, easy to administer, and simple to score.
A minor consideration of the Oxford Knee Score is the wording of a few questions in the survey. It was originally developed in England and some of the questions don’t translate well to other cultures, particularly for a North American audience.
There are also concerns over the response “not at all.” The concern is that this wording is tricky and could mean the opposite of what the patient intended. This has a drastic impact on the score and decreases the reliability of the tool. As a result, new tools have been developed to remedy this issue and are growing in popularity over the Oxford Knee Score.
Permission to use the Oxford Knee Score can be acquired from Isis Innovation Ltd (the technology transfer company of the University of Oxford) via the website https://process.innovation.ox.ac.uk/clinical
- Murray, D. W., Fitzpatrick, R., Rogers, K., Pandit, H., Beard, D. J., Carr, A. J., & Dawson, J. (2007). The use of the Oxford hip and knee scores. Bone & Joint Journal, 89-B(8), 1010-1014. Accessed May 19, 2016. https://online.boneandjoint.org.uk/doi/full/10.1302/0301-620x.89b8.19424?journalCode=bjj