Do I need an x-ray after an ankle sprain?

Ankle sprains are a common occurrence and something that we see frequently at Kaizen.  These injuries can range from a minor, first time roll of the ankle to chronic, recurring ankle sprains that just keep happening - sometimes leaving you hobbling around with an ankle that is swollen and black and blue. 

​Often times these injuries are minor and don't require any x-rays or surgical intervention and can be treated with some physical therapy aimed at gaining strength/stability and proprioception (perception or awareness of the position and movement of the body).

In some injuries, however, you can also have a fracture in the bones of the ankle or even in the foot.  When this happens, we often see avulsion fractures where the force on the ankle from the sprain is so much that it breaks off a portion of the bone with it.

We also sometime see what is called a Jones fracture.  This is a fracture in the base of the 5th metatarsal, a bone in your foot.  The type and severity of these injuries determines how the are treated.  A minor ankle sprain calls for early weightbearing through that foot.

However, if there is a fracture, there needs to be a period of offloading and possibly immobilization depending on the severity and how stable the fracture is.  If the injury is very unstable, it may call for surgery which means even more rest and healing time prior to a more conservative rehab program initially. 

Because of this uncertainty, people often ask if they should get an x-ray or whether or not they need an x-ray before they come see us.  The answer, of course, isn't always clear cut and can varying depending on the context of the injury. 

Fortunately there is a screening tool, called the Ottawa Ankle Rules, that we can use to help us make this decision:

5 Component to Test: 

A. Bony tenderness along distal 6 cm of posterior edge of fibula or tip of lateral malleolus
B. Bony tenderness along distal 6 cm of posterior edge of tibia/tip of medial malleolus
C. Bony tenderness at the base of 5th metatarsal
D. Bony tenderness at the navicular
E. Inability to bear weight both immediately after injury and for 4 steps during initial evaluation

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 mid-foot 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.

This screening tool has a very high negative predictive value which means that if you CAN take 4 steps AND you DO NOT have tenderness in those specific areas, it almost certainly means YOU DO NOT HAVE AN ANKLE FRACTURE and thus you do not need to get an x-ray.
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Now, if you CAN NOT take 4 steps or DO have tenderness in those areas, that does not necessarily mean that you do have a fracture, it just means you should see your physician and get an x-ray.

The specificity (ability of the test to determine if someone has a fracture) of the Ottawa ankle rules is low. It is simply a SCREENING test to RULE OUT if someone has an ankle fracture, not to RULE IN if you do indeed have an ankle fracture. 

ANKLE X-RAY SCREENING QUESTIONS

1. Can you take 4 steps (its okay if need to limp)? NO? –> GET AN XRAY
2. Do you have tenderness/pain around your medial or lateral malleoli (the little bone bumps on either side of your ankle)? Specifically the back side of the bones? YES? –> GET AN XRAY
3. Do you have tenderness/pain around the base of the 5th metatarsal (bump on the lateral/outside portion of your foot; halfway between your heel and your little toe)? YES? –> GET AN XRAY
4. Do you have tenderness/pain around the navicular bone (bump on the medial/inside portion of your foot?) YES> –> GET AN XRAY

References:

Bachmann, L. M., Kolb, E., Koller, M. T., Steurer, J., & ter Riet, G. (2003). Accuracy of Ottawa ankle rules to exclude fractures of the ankle and mid-foot: systematic review. BMJ (Clinical research ed.), 326(7386), 417. https://doi.org/10.1136/bmj.326.7386.417

Physiopedia. (n.d.). Ottawa Ankle Rules. Retrieved August 4, 2020, from https://www.physio-pedia.com/Ottawa_Ankle_Rules
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Lau, M. (2020, February 1). Do I Need an X-Ray After an Ankle Sprain? 𝙏𝙝𝙚 𝙋𝙧𝙚𝙝𝙖𝙗 𝙂𝙪𝙮𝙨 | Online Physical Therapy. https://theprehabguys.com/x-ray-after-an-ankle-sprain/

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