Ottawa Ankle Rules Calculator for Imaging Triage

Calculator Input

Enter injury details, pain zones, tenderness findings, walking ability, and any exclusion flags. The result appears above this form after submission.

Patient Context

Patient Name

Patient ID

Age

Injury Side

Hours Since Injury

Pain Score

Mechanism of Injury

Swelling Level

Pain Zone Selection

Pain in malleolar zone

Select when ankle pain is present around the malleoli.

Pain in midfoot zone

Select when pain localizes to the midfoot region.

Bone Tenderness Findings

Medial malleolus tenderness

Posterior edge or tip of distal tibia.

Lateral malleolus tenderness

Posterior edge or tip of distal fibula.

Navicular tenderness

Use for the midfoot branch.

Base of 5th metatarsal tenderness

Use for the midfoot branch.

Weight-Bearing Assessment

Able to bear weight immediately after injury?

Yes

No

The weight-bearing criterion is positive only when both this answer and the next answer are “No”.

Able to take 4 steps at evaluation now?

Yes

No

Use the walking test exactly as examined.

Validity Check and Caution Flags

Multiple trauma

Or distracting injury.

Altered consciousness

Or intoxication concern.

Pregnancy flag

Triggers caution notice.

Return visit

Same injury reassessment.

This tool structures Ottawa rule inputs for imaging triage. It does not diagnose fracture and should not replace clinician judgment.

Formula Used

Ankle series indicated = Malleolar zone pain AND (medial malleolus tenderness OR lateral malleolus tenderness OR [unable to bear weight immediately AND unable to take 4 steps now]).

Foot series indicated = Midfoot zone pain AND (navicular tenderness OR base of 5th metatarsal tenderness OR [unable to bear weight immediately AND unable to take 4 steps now]).

Triggered criteria count = positive ankle branch findings + positive foot branch findings. The graph visualizes ankle triggers, foot triggers, and exclusion flags for quick review.

How to Use This Calculator

Enter patient context such as age, pain score, injury side, and hours since injury.
Select the relevant pain zone: malleolar zone, midfoot zone, or both if clinically appropriate.
Mark tenderness at the exact anatomic points found on exam.
Answer both weight-bearing questions carefully. The walking criterion turns positive only if both answers are “No”.
Select any caution flags that limit standard rule use.
Submit the form. Review the result summary above the form, the interpretation notes, and the graph.
Use the export buttons to save the result as CSV or PDF.

Example Data Table

Case	Malleolar Pain	Midfoot Pain	Tenderness	Weight Bearing Immediate	4 Steps Now	Outcome
Twisting ankle with lateral tenderness	Yes	No	Lateral malleolus	Yes	Yes	Ankle series indicated
Midfoot pain with navicular tenderness	No	Yes	Navicular	Yes	Yes	Foot series indicated
Diffuse ankle pain, no bony tenderness, walks fine	Yes	No	None	Yes	Yes	No rule trigger found
Severe injury, cannot bear weight at both times	Yes	Yes	None entered	No	No	Ankle and foot series indicated

FAQs

1) What does this calculator do?

It converts Ottawa ankle rule findings into a structured imaging recommendation for ankle and midfoot injury assessment.

2) Does it diagnose a fracture?

No. It supports imaging triage only. Fracture diagnosis still depends on imaging, examination quality, and full clinical judgment.

3) Why are there two walking questions?

The weight-bearing criterion is strongest when the patient cannot bear weight immediately after injury and also cannot complete four steps during assessment.

4) When is ankle imaging indicated?

Ankle imaging is triggered when malleolar pain exists with medial malleolus tenderness, lateral malleolus tenderness, or positive two-part weight-bearing failure.

5) When is foot imaging indicated?

Foot imaging is triggered when midfoot pain exists with navicular tenderness, base-of-fifth tenderness, or positive two-part weight-bearing failure.

6) Why include exclusion flags?

They warn that the entered situation may fall outside standard validation contexts, so the output should be used more cautiously.

7) Can both ankle and foot series be recommended?

Yes. If both pain zones are present and the entered criteria are positive for each branch, both recommendations can appear together.

8) What do the CSV and PDF downloads include?

They include the entered findings, result summary, trigger counts, and interpretation notes so the output can be stored or shared.