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KOOS Calculator

Try a shortened preview of the Knee injury and Osteoarthritis Outcome Score below, free, no account. In a real chart, the full instrument scores automatically and charts every domain over time.

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KOOS, simplified preview

0 of 15 answered

Pain

Pain while walking on a flat surface

Pain going up or down stairs

Pain at night while in bed

Symptoms

Knee swelling

Grinding, clicking, or other noise from the knee

Stiffness after first waking

Function, daily living

Descending stairs

Rising from sitting

Standing for a long time

Function, sport & recreation

Squatting

Running

Twisting or pivoting on your injured knee

Quality of life

Awareness of your knee problem

Modified your lifestyle to avoid damaging the knee

Confidence in your knee

Answer every item to see the domain scores.

This is a shortened, illustrative version. The full instrument has 42 items across these same 5 domains. Nothing here is saved; sign in to score the full version against a real patient.

Knee injury and Osteoarthritis Outcome Score

What the KOOS measures

The Knee injury and Osteoarthritis Outcome Score (KOOS) is a 42-item questionnaire covering five subscales: Pain, Symptoms, Activities of Daily Living, Sport and Recreation, and Knee-related Quality of Life. Roos and colleagues developed it in 1998 for knee injuries that can lead to osteoarthritis.

The calculator above is a shortened preview with three items per subscale, so you can see how the scoring works. It is not the validated instrument. Use the full 42-item KOOS for clinical decisions.

How the full KOOS is scored

Each item is answered on a 5-point scale from 0 (none) to 4 (extreme).
For each subscale, average the item responses.
Transform each subscale to 0–100, where 100 means no problems: 100 − (mean × 100 ÷ 4).

Subscales are reported separately. An aggregate total is not recommended by the developers, because it hides which domain is driving the problem.

Interpreting the subscales

Each subscale is read on its own 0–100 scale:

Subscale	Items in the full KOOS
Pain	9
Symptoms (including stiffness)	7
Activities of daily living	17
Sport and recreation	5
Knee-related quality of life	4

100 means no knee problems and 0 means extreme problems. There are no official severity bands.

What counts as a meaningful change

The developers suggest that a change of about 8 to 10 points on a subscale is clinically meaningful. Later studies report different thresholds depending on the population and the treatment (for example, after knee replacement).

Look at the subscale that matches the patient's goal: Sport and Recreation for a return-to-sport plan, ADL for an older patient with osteoarthritis.

Using the KOOS in your clinic

Physiotherapists use the KOOS for ACL and meniscus rehabilitation, knee osteoarthritis and post-arthroplasty care, where changes in separate subscales guide the plan. In Zdrovia, the score is saved to the chart at each visit and graphed automatically. See how that works for physiotherapy clinics.

Frequently asked questions

How is the KOOS scored?

Average the items in each of the five subscales, then transform to 0–100 with 100 − (mean × 100 ÷ 4). Each subscale is reported separately; 100 means no problems.

Is a higher KOOS score better?

Yes. The subscales are transformed so that 100 means no knee problems and 0 means extreme problems.

What is the MCID for the KOOS?

The developers suggest about 8–10 points per subscale. Published estimates vary by population and treatment.

Is this the full KOOS?

No. The calculator on this page is a 15-item preview to show how subscale scoring works. Use the full 42-item KOOS, which is free to use, for clinical assessment.

Sources

This page is a reference for clinicians, not medical advice. Scoring conventions and change thresholds vary between studies; follow your profession's guidance and the instrument's official user manual.

How it works in the app

Score once. Trend forever.

Drop in the block

Add an Outcome Measure Smart Block to any knee chart template: intake, re-assessment, or discharge.

Score it in the visit

The patient answers, or you do it with them. Each domain score computes live, the same way PHQ-9 and GAD-7 already do in Zdrovia today.

Watch it trend

Every domain score across every visit lands on one chart automatically, no spreadsheet, no re-typing old scores to see if the patient is improving.

No spreadsheet required

Five domains, five lines on one chart

Pain can drop while function stays flat, or the reverse. Keeping the domains separate on the chart, instead of one blended number, is what makes the trend actually useful in a visit.