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[Clinical exam](https://durgical.com/en/clinical-exam/) · [Musculoskeletal system](https://durgical.com/en/clinical-exam/#a-musculoskeletal)

# Ottawa ankle and knee rules

- Topic

A few questions and spots to press help decide whether a twisted ankle or knee needs an X-ray.

Updated 2026-11-01

**See it in 3D:** [Fibula](https://durgical.com/en/anatomy/fibula/) · [Tibia](https://durgical.com/en/anatomy/tibia/) · [Navicular](https://durgical.com/en/anatomy/navicular-bone/) · [Fifth metatarsal](https://durgical.com/en/anatomy/fifth/) · [Patella](https://durgical.com/en/anatomy/patella/)

## Key points

- Ankle: X-ray if there is pain in the malleolar zone and bone tenderness at the posterior edge or tip of either malleolus, or inability to take four steps.
- Foot: X-ray if there is midfoot pain and tenderness at the base of the fifth metatarsal or the navicular, or inability to take four steps.
- Knee: age 55 or over, isolated patellar tenderness, tenderness at the fibular head, cannot flex to 90 degrees or cannot take four steps.
- Very sensitive, not specific: they rule fracture out, not in.
- The four steps count even with a limp; they are judged right after the injury and in the clinic.

## What it is

The Ottawa rules are clinical criteria that pick out which patients with ankle, midfoot or knee trauma need an X-ray to look for a fracture. They are very sensitive: if no criterion is present, a fracture is very unlikely and an unnecessary X-ray is avoided. They are not specific, so a positive criterion does not mean there is a fracture.

## Key facts

- Press firmly on the bone, not the ligament: tenderness over the lateral ligament without bone tenderness suggests a sprain.
- The knee rule is not validated in children; under 12 years other criteria are used.
- They do not apply to intoxicated patients, those with distracting injuries, altered sensation or an injury more than a few days old.
- Nursing and triage: applying the rule on arrival shortens waits and cuts unnecessary X-rays.

## One criterion is enough to order the X-ray.

| Rule | X-ray if there is… | Points to press |
| --- | --- | --- |
| Ankle | Malleolar-zone pain and bone tenderness at a key point, or cannot take four steps | Posterior edge and tip of the lateral and medial malleoli (the distal 6 cm) |
| Foot (midfoot) | Midfoot pain and bone tenderness at a key point, or cannot take four steps | Base of the fifth metatarsal and the navicular bone |
| Knee | Any of: age 55 or over, isolated patellar tenderness, fibular head tenderness, cannot flex to 90 degrees, cannot take four steps | Patella and fibular head |

## Test yourself

Think of the answer, then tap the question to see it.

## Which bony points are pressed in the Ottawa ankle rule?

The posterior edge and tip of the lateral malleolus and of the medial malleolus.

## Which bony points are pressed in the Ottawa foot rule?

The base of the fifth metatarsal and the navicular bone.

## What are the criteria of the Ottawa knee rule?

Age 55 or over, isolated patellar tenderness, fibular head tenderness, inability to flex to 90 degrees or to take four steps.

## Why is a negative Ottawa rule useful?

Because it is very sensitive: with no criterion present, a fracture is very unlikely and the X-ray can be avoided.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/clinical-exam/ottawa-ankle-and-knee-rules/)

## See it in 3D

The structures of Durgical's 3D anatomy where it is found.

- [Fibula](https://durgical.com/en/anatomy/fibula/)
- [Tibia](https://durgical.com/en/anatomy/tibia/)
- [Navicular](https://durgical.com/en/anatomy/navicular-bone/)
- [Fifth metatarsal](https://durgical.com/en/anatomy/fifth/)
- [Patella](https://durgical.com/en/anatomy/patella/)

## Related

- [Lachman test and anterior drawer](https://durgical.com/en/clinical-exam/lachman-test-and-anterior-drawer/)
- [Thompson test](https://durgical.com/en/clinical-exam/thompson-test/)
- [Knee effusion: patellar tap and bulge sign](https://durgical.com/en/clinical-exam/knee-effusion-patellar-tap-and-bulge-sign/)
- [Joint examination: inspection, palpation and range of motion](https://durgical.com/en/clinical-exam/joint-examination-inspection-palpation-and-range-of-motion/)

## Related conditions

- [Ankle fracture](https://durgical.com/en/conditions/ankle-fracture/)
- [Lateral Ankle Sprain](https://durgical.com/en/conditions/lateral-ankle-sprain/)
- [Patellar fracture](https://durgical.com/en/conditions/patellar-fracture/)

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Educational content on the clinical exam; it is learned and practised under supervision. It does not replace assessment by a health professional and is not for self-diagnosis.

Sources: [Ottawa Rules Simplify the Management of Ankle Injuries](https://www.aafp.org/pubs/afp/issues/2003/0815/p745a.html) (American Family Physician (American Academy of Family Physicians), 2003); [Evaluating the Patient with a Knee Injury](https://www.aafp.org/pubs/afp/issues/2005/0315/p1169.html) (American Family Physician (American Academy of Family Physicians), 2005).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/clinical-exam/ottawa-ankle-and-knee-rules/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/clinical-exam/ottawa-ankle-and-knee-rules/