1 Before you use it
What it is
The default knee PROM and the green substitute for both WOMAC and the Oxford Knee Score. Forty-two items across five subscales — pain, symptoms, activities of daily living, sport and recreation, and knee-related quality of life.
KOOS-12 and KOOS-PS are the short forms.
When to reach for it
Knee osteoarthritis, meniscal injury, ligament injury — baseline, decision points, and post-operatively.
In an ACL population, pair it with IKDC and ACL-RSI. KOOS covers the knee, IKDC the symptoms and sport, ACL-RSI the head.
2 Giving it
Scoring
Five subscales, each 0–100, where 100 is no problems. Report them separately — a single KOOS total is not a thing.
WOMAC is contained within KOOS, so a KOOS gives you a WOMAC without the WOMAC licence.
What it doesn’t measure
Strength, hop performance or limb symmetry — the return-to-sport battery sits entirely outside it.
And it doesn't measure activity level. Use Tegner or Marx.
Repeat it
3 Reading the score
Interpreting it
Higher is better. Interpret against baseline.
Sport/recreation and quality of life are the subscales that discriminate. In knee OA, the QoL subscale is often the one that moves the patient's decision about surgery.
Is the change real?
On placement
Knee OA, 64 years old, after a 12-week programme. KOOS Pain 50 → 64; ADL 58 → 66; QoL 25 → 44.
Read it as for someone this age the MDC is 20 points or more per subscale (14.3–19.6 in younger people; measured in knee injury and osteoarthritis). QoL is up 19 — the only one near the line; Pain and ADL are inside error. The library carries no KOOS MCID.
Do QoL is the subscale that moves the surgery conversation in knee OA, so that is the one to report and the one to keep asking about. Don't sell the Pain change as proven.
Student trap. Reporting one KOOS number. Five subscales, reported separately — and the two that matter most are the two people skip.
Official source: koos.nu. We don't host the form.
This is a learning tool. It does not diagnose patients and does not replace your clinical educator.
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