Do I Need an X-Ray After an Ankle Sprain?

You just had a BAD ankle sprain. It’s black and blue. It hurts like hell. How do you know that its ONLY an ankle sprain, and not anything worse like a FRACTURE?! Well lucky for you, there’s a quick an easy test you can do NOW to screen if you need an x-ray after an ankle sprain.

Ankle sprains are one of the most common athletic injuries. Many are just minor ankle sprains, and don’t require any x-rays or surgical treatment. A comprehensive rehabilitation plan is all that’s needed to gain back proprioception and stability in the ankle (READ: Ankle Sprain Rehabilitation). However, in more serious injuries, there can also be FRACTURES of the bones of the ankle and foot as well. Many times these injuries are a specific type of fracture called an avulsion fracture, in which the force on the ligament is so strong that it literally breaks off a portion of the bone with it (remember, ligaments attach bones to other bones).

x-ray after ankle sprain jones fractureIt’s important to screen for these types of injuries because early weightbearing is usually encouraged for minor ankle sprains; however, if there is a fracture, there needs to be a slight period of offloading or even immobilization – depending on the stability of the fracture. Furthermore, more serious fractures like Jones fractures (fracture of the base of the 5th metatarsal) need a longer period of immobilization or even surgery. This area receives less blood flow than other areas in the foot, and thus requires more rest/healing time and a more conservative rehab program from the beginning.

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

 

This battery of screening tests, called the Ottawa Ankle Rules, has an extremely high negative predictive value. What this means, is 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 xray!!

Now, if you CAN NOT take 4 steps or DO have tenderness in those areas, THAT DOES NOT NECESSARILY MEAN YOU HAVE A FRACTURE – it just means you should go to the ED and get an xray. 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. It has a sensitivity of almost 100% I know this was a bit complicated…brings me back to statistics 101 in college…so let us know if you have any questions!!

10 thoughts on “Do I Need an X-Ray After an Ankle Sprain?

  • You may want to clarify that the Ottowa ankle rules state that tenderness to the malleoli is only significant if it is on the distal posterior 6cm.
    As tenderness found anteriorly can lead to a false positive. Simple (Grade 1 -2) ATFL tears can very commonly present with bony tenderness anteriorly with no actual bony involvement.

    • Correct. Will make the change. We write our posts with the average joe in mind, so we try to simplify things and make them understandable for readers of all backgrounds. Thanks for the feedback Bluey!

  • I don’t know all of the terminology but Bluey is right. Tenderness doesn’t tell me anything. I’ve sprained both of my ankles so many times that I’ve lost count. I’ve had almost every incident x-rayed, usually after a few days once the blood starts pooling below my ankle(freaking me out), all of which had tenderness (that comes with the territory…. so yeah) and none of them showed a break or a fracture, period. Tenderness and pain come with injuries so maybe a type of measurement like a type of pain? Or degree or something?

  • Big question in my experience is what to do as a physioyltherapist when the patient has pain in chronic case (for example after 1 year of sprain)

  • I believe these rules were modified to be more specific… Palpation of the crest of the 6cm of the distal tib and fib. This is often termed the Buffalo revised Ottawa ankle rules or the buffalo rule.

  • On #2, it hurts when I press the outer side of the bone bump on the outside of my foot close to the heel, but it does not hurt on the backside of that bone bump. So did I pass or fail test #2?

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