Ankle Injury Assessment Calculator

The Ottawa Ankle Rules are clinical decision guidelines developed to help physicians determine when ankle and foot X-rays are necessary after acute ankle injuries. Introduced in 1992, these rules have been extensively validated and are widely used in emergency departments worldwide.

Clinical Application

The rules apply to patients aged 5 years and older presenting with pain in the malleolar zone or midfoot area. They cannot be used if the patient is intoxicated, has other distracting injuries, has diminished sensation in legs, or has gross swelling preventing palpation.

Ankle Series Indications

An ankle X-ray series (AP, lateral, and mortise views) is required only if there is pain in the malleolar zone AND any of these findings: bone tenderness at the posterior edge or tip of the lateral malleolus (within 6 cm), bone tenderness at the posterior edge or tip of the medial malleolus (within 6 cm), or inability to bear weight both immediately after injury and in the emergency department (defined as unable to take 4 steps).

Foot Series Indications

A foot X-ray series (AP, lateral, and oblique views) is required only if there is pain in the midfoot zone AND any of these findings: bone tenderness at the base of the 5th metatarsal, bone tenderness at the navicular bone, or inability to bear weight both immediately and in the emergency department.

Clinical Impact

Implementation of the Ottawa Ankle Rules has been shown to reduce unnecessary radiography by 30-40% without missing clinically significant fractures. The rules have near-perfect sensitivity (98%) for detecting fractures, meaning they rarely miss fractures when followed correctly. This reduces healthcare costs, radiation exposure, and waiting times in emergency departments.