Lightning Learning: Ottawa Ankle Rules
““Does your patient really need that ankle x-ray? Luckily there is a handy ruleset that can help you decide!””
What?
Ankle x-ray if pain in Malleolar zone, and any of…
Bone tenderness – distal 6cm of posterior edge of the tibia or tip of medial malleolus.
Bone tenderness – distal 6cm of posterior edge of the fibula or tip of lateral malleolus.
Unable to weight bear immediately and in the department for 4 steps.
Foot x-ray if pain in mid-foot and…
Bone tenderness at base of 5th metatarsal
Bone tenderness at navicular bone
Unable to weight bear immediately and in the department for 4 steps.
Why?
The Ottawa Ankle Rules are a validated tool to identify those needing ankle/foot x-rays. They are sensitive (i.e. can rule out fractures), but are not overly specific (i.e. there will be false positives).
Using the rules can reduce the number of unnecessary x-rays by up to 30%
There are limitations:
Intoxicated or uncooperative patients
Distracting painful injuries
Poor sensation in the legs
Gross swelling preventing palpation of bone tenderness
They can also be applied to children with some caveats (see links in Further Reading)
