Ankle injuries are very common injuries and not all ankle injuries require x-ray evaluation. Ottawa ankle rules for ankle injury radiography is an attempt to answer when the x-rays should be done in cases of ankle injuries.
Because the rule is sensitive and not specific, it provides a clear guide of which patients not to x-ray if all criteria are met. However, if a patient fails the criteria, the need for x-ray can be left to clinical judgment
What are Ottawa ankle rules for ankle injury radiography?
An ankle x-ray series is only required if there is any pain in the malleolar zone and any of these findings:
- Bone tenderness at the posterior edge or tip of the lateral malleolus
- Bone tenderness at the posterior edge or tip of the medial malleolus
- Inability to take 4 complete steps both immediately after the injury and in the emergency department
A foot x-ray series is only required if there is any pain in the midfoot zone and any of these findings:
- Bone tenderness at the base of the 5th metatarsal
- Bone tenderness at the navicular
- Inability to take 4 complete steps both immediately and in the ED
Application of Ottawa Ankle Rules
Before deciding whether an x-ray needs to be done
- Palpate the entire distal 6 cm of the fibula and tibia
- Look for medial malleolar tenderness
- Do not use for patients under age 18 years
However, in the following situations, the clinician should base judgment on the clinical hitch rather than sticking to the Ottawa ankle rules
- Intoxicated or uncooperative patient
- Presence of other distracting painful injuries
- Diminished sensation in the legs
- Presence of gross swelling that prevents palpation of malleolar bone tenderness
- If ankle pain is present and there is tenderness over the posterior 6 cm or tip of the posterior or lateral malleolus, then an ankle-ray is indicated.
- If the midfoot pain is present and there is tenderness over the navicular or the base of the fifth metatarsal, then a foot-x-ray is present.
- If there is ankle or midfoot pain and the patient is unable to take four steps both immediately and in the emergency department, then an x-ray of the painful area is indicated.
Patients who fulfill none of the Ottawa ankle criteria do not need an ankle or foot x-ray. Those that fulfill either the foot or ankle criteria need an x-ray of the respective body part.
Ottawa Ankle Rules in Children.
Research has shown Ottawa ankle rules to be 100% sensitive for both clinically significant ankle and midfoot fractures. It was noted that ankle x-rays could be reduced by 16% and foot x-rays by 29% with these rules.
Stiell IG, Greenberg GH, McKnight RD, Nair RC, McDowell I, Worthington JR. A study to develop clinical decision rules for the use of radiography in acute ankle injuries. Ann Emerg Med. 1992; 21:384–90.