Clinical Decision-Making in Acute Ankle Injuries

Ankle injuries comprise a large number of the total number of musculoskeletal injuries that visit our clinical practices annually. While many ankle injuries happen in the sporting environment, a large number also happen during activities of daily living. Between para-medicine, family practice, and the emergency room, the injured often ask the same question:“should I be getting an x-ray?” In recent years there has been plenty of discussion around the utility of imaging and when it should, or should not, be used as part of patient care. While many individuals undergo imaging following an ankle injury, less than 15% have fracture.²

In 1992, researchers at the University of Ottawa attempted to answer this question and made guidelines for ordering imaging following ankle injury. These guidelines were first published over 30 years ago (Stiell et al., 1994).¹ The purpose of these guidelines was to better guide practitioners in making decisions around when an x-ray of the ankle and foot may be warranted and when referrals were to be made. 

As a clinician, the great thing about the “Ottawa ankle rules” is they are simple to implement into your practice. The rules are based on findings in the physical exam and how the injured person is presenting in your office. The rules paired with mechanism of injury can help better guide clinical decision making.

The Rules

1. Inability to bear weight immediately following the injury and while in your office. 
2. Bone tenderness on palpation of the following areas: posterior edge, or tip, of the medial, or lateral, malleolus (the most distal 6cm), the base of the 5th metatarsal or the navicular.  

There are a few other considerations that I add in my practice as an adjunct to the Ottawa ankle rules. One of them is visual inspection of the injured ankle; swelling and bruising are common following an ankle injury. I will ask questions about how quickly and significantly the onset of bruising and swelling occurred. I’ve had several people over the years describe their confidence as it pertains to weight-bearing along these lines: “it’s not necessarily the pain, I just don’t feel confident in standing on it, it’s hard to explain.” It’s important to ask about their ability to bear weight given that pain will not always be the most obvious symptom. Lastly, mechanism of injury sheds light on the potential severity of the injury. I like to ask if the person felt a “pop, snap, crack, or click” when they got injured, since it can help determine severity of the mechanism of injury. While these tools are not a perfect science I’ve found that they help round out the use of the Ottawa ankle rules nicely. 

Following questions and inspection of the ankle, a clinician can then form a decision around the need for imaging. If the person is in a grey zone where the clinician is unsure about the injury, it makes sense to be cautious. It’s a benefit to the clinician that the Ottawa ankle rules are a reasonably sensitive method of examination. High sensitivity means that when a clinician finds positive associated findings on an exam (for example, inability to bear weight), the likelihood that the condition they are examining for (in this case ankle fracture) is more likely to be present. Researchers have found that the Ottawa ankle rules range in sensitivity from  96.4% to 99.6% (Bachmann et al., 2003).² In more recent years, researchers found much broader ranges of sensitivity for the Ottawa ankle rules, ranging from 59% to 100% (Gomez et al., 2022).

Specificity is also important to note, and the Ottawa ankle rules have a much lower specificity. Specificity is when a lack of findings on a physical examination indicate that a condition is not present. For example: there is no pain on the palpation of the ankle and foot, therefore there is no presence of fracture. Researchers found specificity ranged from 2% to 69% in the case of the Ottawa ankle rules. Speculation as to the wide range of specificity in studies may be due to clinicians’ individual interpretation of findings and/or the experience of the individuals performing the clinical exams.⁴ 

My Thoughts 

When considering a referral for imaging it’s always helpful to have information that guides you. The Ottawa ankle rules is something I have been using in my practice since its infancy. It allows me to feel confident that I have a taken an evidence-based approach to my decision making in clinic. 

The rules paired with how the ankle looks, the information that the injured person has provided, along with the mechanism of injury helps me take the immediate next steps in care. If therapy begins and doesn’t seem to be trending in the right direction, a referral for imaging can always be made. 

How do you evaluate ankle injuries in your practice? Has the Ottawa ankle rules helped guide you along the way? We’d love for you to share your stories in the comments!