Clinical exam · Musculoskeletal system
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 · Tibia · Navicular · Fifth metatarsal · Patella
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.
See it in 3D
The structures of Durgical's 3D anatomy where it is found.
Related
- Lachman test and anterior drawer
- Thompson test
- Knee effusion: patellar tap and bulge sign
- Joint examination: inspection, palpation and range of motion
Related conditions
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 (American Family Physician (American Academy of Family Physicians), 2003); Evaluating the Patient with a Knee Injury (American Family Physician (American Academy of Family Physicians), 2005).
Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake
Representative model, for educational purposes only.