06/01/2024
Ottawa Ankle Rules
Purpose
The Ottawa Ankle Rules determine the need for radiographs in acute ankle injury This screening tool was developed because of the need for a rapid and accurate way to avoid unnecessary imaging.
Ankle sprain are a common occurrence in athletes as well as the general population. It is estimated that approximately 25,000 ankle sprains occur per day in the USA which equates to 1 sprain per 10,000 daily A meta-analysis carried out by Doherty et al., 2014 demonstrated a higher incidence of ankle sprain in females compared with males (13.6 vs 6.94 per 1,000 exposures), in children compared with adolescents (2.85 vs 1.94 per 1,000 exposures) and adolescents compared with adults (1.94 vs 0.72 per 1,000 exposures)
The management of ankle sprains is a daily routine at emergency departments. Traditionally, physicians would order radiographs for all ankle injuries, although less than 15% would have a clinically significant fracture, and add to healthcare costs. The Ottawa Ankle Rules were established to help physicians decide which patients should have an x-ray following an acute ankle injury.
Evidence supports the Ottawa ankle rules 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%. A patient who presents with 0 of the symptoms is less than 1% likely to have a fracture
Variables
5 Component to Test:
Bony tenderness along distal 6 cm of the posterior edge of fibula or tip of lateral malleolus
Bony tenderness along distal 6 cm of the posterior edge of tibia/tip of medial malleolus
Bony tenderness at the base of the 5th metatarsal
Bony tenderness at the navicular
Inability to bear weight both immediately after injury and for 4 steps during initial evaluation
Method of Use
An Ankle X-ray is only required if
There is any pain in the malleolar zone; and,
Any one of the following:
Bone tenderness along the distal 6 cm of the posterior edge of the tibia or tip of the medial malleolus, OR
Bone tenderness along the distal 6 cm of the posterior edge of the fibula or tip of the lateral malleolus, OR
An inability to bear weight both immediately and in the emergency department for four steps.
A foot X-ray series is indicated if:
There is any pain in the midfoot zone; and,
Any one of the following:
Bone tenderness at the base of the fifth metatarsal (for foot injuries), OR
Bone tenderness at the navicular bone (for foot injuries), OR
An inability to bear weight both immediately and in the emergency department for four steps.
It must be noted that certain groups are excluded, in particular pregnant women, those with diminished ability to follow the test (for example; head injury or intoxication). Several studies strongly support the use of the Ottawa Ankle Rules in children over 6 (98.5% sensitivity). However, their usefulness in younger children has not yet been thoroughly examined.
The original rules were developed for ankle and foot injuries only, but similar guidelines have been developed for other injuries
Recommendations
Ensure to apply the Ottawa Ankle Rules accurately by
Palpating the entire distal 6cm of the tibia and fibula
Not neglecting the importance of medial malleolar tenderness
Using the rules only on those over the age of 18
Be sure to give written instructions and encourage follow-up in 5-7 days if pain and walking ability have not improved.
Evidence
A systematic review of 27 studies by Bachmann et al found the pooled sensitivity of the Ottawa Ankle Rules to be 97.6%, with a median specificity of 31.5%. The pooled negative likelihood ratio for the ankle and midfoot were 0.08 and 0.08 respectively whereas in children it was 0.07. The authors applied these ratios to the reported 15% fracture prevalence and determined the probability of a fracture after negative testing following the implementation of the Ottawa Ankle Rules to be less than 1.4%. The authors concluded the instrument should reduce the number of unnecessary radiographs by 30-40%.
Reliability
The Ottawa Ankle Rules have been found to have sensitivities of 1.0 (95% confidence interval (CI), .95-1.0) for detecting malleolar fractures and 1.0 (95% CI, .82-1.0) for detecting midfoot fractures.
Accuracy
A systematic review of 27 studies found a 1.73% (95% CI, 1.05-2.75) probability of a fracture after negative testing when implementing the Ottawa Ankle Rules. When implemented less than 48 hours after injury, the fracture probability went to 1.05 (95% CI .35-3.24).
Validity
In children aged 2-16, the Ottawa Ankle Rules were found to have a sensitivity of 1.0 (95% CI, .95-1.0) for malleolar fractures and 1.0 (95% CI, .82-1.0) for midfoot fractures.
Clinical Significance
When implementing the Ottawa Ankle Rules in the emergency or clinic setting, the relative reduction in ankle radiography was reduced by 28% compared to a 2% increase in a control setting not using the rules (P
