Ottawa Ankle Rules | Ankle Fracture Assessment & screening

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The Ottawa Ankle Rules | Ankle Fracture Clinical Prediction Rule

The Ottawa Ankle Rules (OARs) are a highly valid screening tool to assess for fractures of the tibia, fibula, 5th metatarsal, and navicular bone.

They have been developed to reduce the need for radiographs after acute trauma. A review by Bachmann et al. (2003) rated the sensitivity between 96.4 to 99.6% and the specificity at 26.3 to 47.9%. Applying these ratios to a 15% prevalence of fracture gave a less than 1.4% probability of actual fracture in these subgroups.

In conclusion, evidence supports the OARs as an accurate instrument for excluding fractures of the ankle and mid-foot. The instrument has a sensitivity of almost 100% and a modest specificity, and its use should reduce the number of unnecessary radiographs by 30-40%

Execution:

1) Palpate for tenderness on the posterior edge of the lateral and medial Malleolus: start distally and move six centimeters upwards.

2) Then palpate for pain or tenderness over the navicular bone and fifth metatarsal.

3) For the last criterion, ask the patients to walk four consecutive steps. It doesn’t matter how the patient is walking, he might as well be limping.

If your patient reports pain upon steps 1 or 2 and is not able to walk 4 consecutive steps, the OARs are rated as positive.
Be aware that this doesn’t mean that there is a high chance for a fracture (still below one 1 out of 3 due to the low sensitivity), but we cannot safely rule out a fracture.