Chief Complaint: Ankle Injury–Does this patient have a fracture?
Author: David Sacolick, MS4 // Editor: Michael Barrie, OSU EM Attending
Musculoskeletal injuries are common chief complaints in both emergency medicine and primary care settings. In particular, over 5 million ankle injuries occur in the United States each year. This patient population includes both young active patients as well as elderly patients. And while ligamentous sprains are more common, fractures are also common and can have long term consequences if not appropriately treated.
When a patient presents with a chief complaint of an ankle injury, how do you answer the question: Does this patient have a fracture?
A 31 year old female with no significant past medical history presents to the emergency department by squad with a chief complaint of ankle pain. She reports that she was carrying her newborn baby (in a car seat), and while walking down a flight of stairs she slipped and fell. She says she stepped on a book with her left foot and fell onto her right ankle. She does not recall if her ankle rolled in or out, but she does remember feeling a pop and being in immediate pain. Fortunately, her young child was unharmed, but the patient was unable to stand and so her parents called 911.
She describes severe pain all around her right ankle, without any numbness or tingling in her foot. She denies any other injuries, and reports no head trauma or loss of consciousness.
Her vital signs are normal, but the patient is in visible discomfort. Her right ankle is swollen and she is tender to palpation at both the medial and lateral malleoli. She does not have pain about her 5th metatarsal or navicular. She has a 2+ dorsalis pedis pulse and no neurologic deficits in her foot. She is able to motor her toes but not her ankle. The remainder of her exam is unremarkable.
What is your primary concern with these history and physical exam findings? Does this patient need an X-ray?
This patient’s story and exam findings are concerning for an ankle fracture and she requires an x-ray for further evaluation. While ankle injuries are common chief complaints in an emergency department, a fracture is found in less than 15% of these cases. To address this, the Ottawa Ankle Rules were developed to help determine which patients require radiography. A systematic review of 27 studies reporting on 15,581 patients found the Ottawa ankle rules to be 97.6% sensitive and 39.8% specific for ankle fractures. Importantly, the negative predictive ratio was 0.08, with false negative rate of less than 2%. This means the Ottawa ankle rules are very good at ruling out an ankle fracture.
Ottawa Ankle Rules
- Inability to walk 4 steps immediately following the injury or in the Emergency Department
- Tenderness on the posterior edge or tip of medial malleolus
- Tenderness on the posterior edge or tip of lateral malleolus
The patient in this case had positive findings for all components of the Ottawa Ankle Rules, and her x-ray revealed a trimalleolar fracture of the ankle. Another important teaching point is the utility of full length tib-fib films to rule out a proximal fibular (Maisonneuve) fracture — which in the case of this patient was negative. Orthopaedics was consulted and the patient’s ankle fracture was reduced and splinted with fluoroscopy. She was scheduled for surgical fixation of her ankle fracture.
Take-home point: Ankle injuries are common, and the Ottawa ankle rules are very helpful in determining who needs radiography.
- Koehler SM, Eiff P. Overview of Ankle Fractures in Adults. Post TW, ed. UpToDate. Waltham, MA: UpToDate Inc. http://www.uptodate.com (Accessed on November 30, 2017.) https://www.uptodate.com/contents/overview-of-ankle-fractures-in-adults
- Koval, Kenneth J., and Joseph D. Zuckerman. Handbook of Fractures. Lippincott Williams & Wilkins, 2010.
- Bachmann LM, Kolb E, Koller MT et-al. Accuracy of Ottawa ankle rules to exclude fractures of the ankle and mid-foot: systematic review. BMJ. 2003;326 (7386): 417. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC149439/