What are the Ottawa Rules?

From the Guidelines

The Ottawa Rules are a set of clinical decision rules used to determine the need for radiographs in patients with acute foot or ankle injuries, and they state that a series of foot radiographs is required only if there is pain in the midfoot and any one of the following: 1) point bone tenderness of the navicular; 2) point bone tenderness of the base of the fifth metatarsal; or 3) inability to bear weight or to walk 4 steps. These rules have been shown to have a high sensitivity of 99% and a median specificity of 26% for combined evaluation of the ankle and midfoot 1. The Ottawa Rules have been validated in various studies, including a meta-analysis of 10 studies encompassing 3,725 patients, which demonstrated their effectiveness in minimizing unnecessary radiographs 1. Some key points to consider when applying the Ottawa Rules include:

• The rules are effective for the pediatric population (>5 years of age) 1
• The addition of swelling as a criterion yields a sensitivity and specificity for fracture of 100% and 55% for the malleolar zone and 50% and 40% for the midfoot, respectively 1
• The rules have been shown to correctly rule out fracture, without using radiography, in 299 out of 300 patients 1 It is essential to note that the Ottawa Rules are not limited to foot injuries, as there are also rules for ankle and knee injuries, such as the Ottawa Ankle and Foot Rules and the Ottawa Knee Rule, which have their own set of criteria for determining the need for radiographs 1.

From the Research

Definition and Purpose of the Ottawa Rules

• The Ottawa ankle rules (OAR) are clinical decision guidelines used to identify whether patients with ankle injuries need to undergo radiography 2, 3.
• The purpose of the Ottawa rules is to reduce unnecessary radiography and to detect clinically significant ankle fractures 2, 3.

Application and Validation of the Ottawa Rules

• The Ottawa rules have been validated and refined through prospective studies, showing high sensitivity and modest specificity for the diagnosis of fractures associated with acute ankle injury 2, 3.
• The rules have been found to be applicable in different populations, including the Chinese population 2.
• The application of the Ottawa rules can decrease unnecessary radiographs by 31.1% to 34% 2, 3.

Key Findings and Implications

• The Ottawa rules have been shown to have nearly perfect sensitivity for identifying clinically significant ankle fractures 2, 3.
• The rules may detect some occult fractures of the malleoli that are not visible on radiographs 2.
• The use of the Ottawa rules can lead to a reduction in radiation exposure and more efficient use of resources 4.
• Compliance with the Ottawa rules can be improved through education and periodic audits 4.

Related Rules and Applications

• The Ottawa Knee Rule is a related clinical decision rule that has been developed to allow physicians to be more selective and efficient in their use of plain radiography for patients with acute knee injuries 5.
• The implementation of the Ottawa Knee Rule has been shown to lead to a decrease in the use of knee radiography without patient dissatisfaction or missed fractures 5.