What are the Ottawa Ankle Rules?

The Ottawa Ankle Rules are validated clinical criteria published in 1992 that identify which patients need ankle X-rays after acute injury. They have near 100% sensitivity for fractures and reduce unnecessary imaging by 30–40%.

Is pain in the malleolar zone required?

Yes. The ankle-series pathway applies when there is pain in the malleolar zone. An ankle X-ray is indicated when that pain is present plus posterior malleolar bone tenderness or inability to bear weight for four steps both immediately after injury and during assessment. Midfoot pain is evaluated with the separate Ottawa foot rule.

What does "bear weight" mean in this context?

The patient must be able to take four full steps immediately after injury and in the emergency department, regardless of limping. If they can manage four steps, they can bear weight even if it is painful.

Where exactly is the posterior edge of the malleolus?

The posterior 6 cm of the distal fibula (lateral malleolus) or distal tibia (medial malleolus). Tenderness anywhere in this 6 cm zone — not just the malleolar tip — is a positive finding.

Who should not be assessed with these rules?

The Ottawa Ankle Rules apply to adults (18 years and older) presenting within 10 days of acute ankle injury. Do not apply to children under 18, pregnant patients, patients with diminished limb sensation, or those re-presenting after prior Ottawa-negative assessment.

How accurate is this tool?

Multiple prospective validation studies show sensitivity of 96–100% for clinically significant ankle fractures. A negative result (no X-ray required) is highly reliable; a positive result warrants radiographic imaging per standard protocol.

Ankle Fracture Risk (Ottawa Rules)

Confirm pain in the malleolar zone, then check bone tenderness and weight-bearing status to determine whether an ankle X-ray is indicated.

Ottawa Ankle Criteria

Is there pain in the malleolar zone?

Required before applying the ankle-series tenderness and weight-bearing criteria.

Yes No

Can the patient bear weight?

Able to take 4 steps immediately after injury AND on examination, regardless of limping.

Yes No / Unable

Point tenderness present at:

Palpate the posterior 6 cm of each malleolus. Check all that apply.

Posterior edge or tip of lateral malleolus

Distal 6 cm of fibula (outer ankle)

Posterior edge or tip of medial malleolus

Distal 6 cm of tibia (inner ankle)

Fracture Risk Assessment

Answer the malleolar-zone pain and weight-bearing questions to see the assessment.

Clinical note: The Ottawa Ankle Rules apply to adults ≥18 years presenting within 10 days of acute ankle injury. Not validated in children, pregnant patients, or those with impaired sensation. Clinical judgment always takes precedence.

Summary

Confirm pain in the malleolar zone, then check bone tenderness and weight-bearing status to determine whether an ankle X-ray is indicated.

How it works

Confirm whether pain is present in the malleolar zone, the prerequisite for the ankle-series rule.
Answer whether the patient can bear weight on the injured ankle.
Check any areas of point tenderness present on examination.
The tool applies the Ottawa ankle-series prerequisite and criteria to the imaging decision.
A recommendation to obtain or skip X-ray is displayed instantly.
Reset to start a new patient assessment.

Use cases

Triage ankle injuries in emergency or urgent care settings.
Decide whether to order ankle X-rays for acute trauma patients.
Teach the Ottawa Ankle Rules to medical students and residents.
Document clinical reasoning for imaging decisions in ankle injuries.
Screen athletes for fracture risk at the sideline before imaging.

Frequently Asked Questions

Last updated: 2026-09-19 · Reviewed by Nham Vu