Oxford Knee Score

Original Editor - Lauren Lopez Top Contributors - Lauren Lopez, Gunilla Buitendag and Aminat Abolade

Original Editor - Your name will be added here if you created the original content for this page.

Top Contributors - Lauren Lopez, Gunilla Buitendag and Aminat Abolade  

Objective

The Oxford Knee Score (OKS) was developed in 1998 and validated to measure pain and function after total knee replacement.

Intended Population

The OKS was originally developed and validated for use with individuals undergoing knee arthroplasty but has also been used to measure outcomes in pharmacological treatments, post osteotomies, following rehabilitation or with fractures. It is a primary outcome measure of choice for national audits of knee replacements. It has also been used to predict revisions six months after a replacement.

Method of Use

The OKS is a patient reported outcome measure that consists of 12 questions about an individual's level of function, activities of daily living and how they have been affected by pain over the preceding four weeks.

The questionnaire can be completed by the patient individually on paper or digitally. A recent study suggests that there is no clinical difference collecting the data verbally compared to written, both before and after a total knee arthroplasty. This may be useful for patients who cannot complete otherwise and the test can be administered telephonically as an alternative.

Questions

The patient is first asked to date the questionnaire and confirm which knee is affected. If both knees are involved, a questionnaire is done for each leg.

From Dawson et al 1998 and Oxford University Innovation

Questions	Scoring
How would you describe the pain you usually have from your knee?	None Very mild Mild Moderate Severe
2. Have you had any trouble with washing and drying yourself (all over) because of your knee?	No trouble Very little trouble Moderate trouble Extreme difficulty Impossible to do
3. Have you had any trouble getting in and out of a car or using public transport because of your knee? (whichever you tend to use)	No trouble Very little trouble Moderate trouble Extreme difficulty Impossible to do
4. For how long have you been able to walk before the pain from your knee becomes severe (with or without a stick)	No pain/more than 30 minutes 16 to 30 minutes 5 to 15 minutes Around the house only Not at all/pain severe when walking
5. After a meal (sat at a table), how painful has it been for you to stand up from a chair because of your knee?	Not at all painful Slightly painful Moderately painful Very painful Unbearable
6. Have you been limping when walking, because of your knee?	Rarely/ never Sometimes, or just at first Often,not just at first Most of the time All of the time
7. Could you kneel down and get up again afterwards?	Yes, easily With little difficulty With moderate difficulty With extreme difficulty No, impossible
8. Have you been troubled by pain from your knee in bed at night?	No nights Only 1 or 2 nights Some nights Most nights Every night
9. How much has pain from your knee interfered with your usual work (including housework)?	Not at all A little bit Moderately Greatly Totally
10. Have you felt that your knee might suddenly “give way” or let you down?	Rarely/ never Sometimes, or just at first Often, not just at first Most of the time All of the time
11. Could you do the household shopping on your own?	Yes, easily With little difficulty With moderate difficulty With extreme difficulty No, impossible
12. Could you walk down a flight of stairs?	Yes, easily With little difficulty With moderate difficulty With extreme difficulty No, impossible

Scoring

When the OKS was originally developed, it was designed to be as simple as possible for ease of use. The original scoring system was a 1-5 where one represented the best outcome. However, clinicians found this confusing in practice and adaptations began to appear so the original authors developed a new scoring system from 0-4 where four is the best outcome and total scores range from 0 (poorest function) to 48 (maximal function).

If there are more than two missing answers, it is recommended that the overall score should not be calculated. In the event one or two questions are unanswered, it is recommended that clinicians calculate a mean score from the patient's other answer. If a question has more than one answer, the worst response i.e. smallest number is used for calculations.

Mikkelsen et al. recently created a clinical meaningful classification of the change scores (ΔOKS). The results suggest that four categories can be distinguished when comparing the ΔOKS:

1. much better (≥16)
2. a little better (7-15)
3. about the same (1-6)
4. much worse (≤0)

Equipment

Pen and paper or online calculator.

Resources

Original article by Dawson et al 1998.

Useful information on background and use of The Oxford Knee Score by Oxford University Innovation.

Evidence

Reliability

The OKS has demonstrated strong test-retest reliability in its original testing. A 2016 systematic review of 23 studies found good evidence of its reproducibility.

Validity

OKS shows significant correlation with similar measures (American Knee Society Score, SF-36, Health Assessment Questionnaire), particularly the pain and physical function domains. A 2016 systematic review (23 studies) found good evidence for its internal consistency and construct validity.

Responsiveness

Research suggests the OKS is responsive to change post operatively and a change of four or more points represents "real" change for an individual while a change of seven or more points represents "clinically relevant".

Miscellaneous

Research suggests that the OKS should not be used to decide whether or not an individual should have surgery because it can be biased in regards to gender, older age and to individuals reporting worse symptoms in order to meet criteria for surgery. Instead, the individual's pain symptoms should be considered.

The OKS is available in multiple languages.