09 Apr 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).
It’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
- Can you take 4 steps (its okay if need to limp)? NO? –> GET AN XRAY
- 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
- 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
- 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!!