Should I have an X-ray taken for an ankle sprain?

An ankle sprain normally occurs following sudden twisting or sideways movements of the ankle. When we sprain our ankle, one or more ligaments in our ankle joint is injured. Ligaments are structures that limit and control excessive movements in our joints. When we sprain a ligament, it simply means that the ligament is over-stretched or partially or completely torn.

Common symptoms associated with ankle sprains include pain and swelling, and sometimes bruising. The extent of the injury correlates well with the degree of symptoms experienced. If you have significant symptoms following an ankle sprain, do seek medical attention. Signs that should raise concern includes:

• Inability to walk on the ankle
• Significant swelling
• Pain in the foot or above the ankle
• Symptoms that persists beyond a few days or do not improve

It may be difficult to differentiate between an ankle sprain and an ankle fracture and sometimes an X-ray may be required. A team at the department of emergency medicine in Ottawa, Canada came up with the “Ottawa ankle rules”.

The Ottawa ankle rules are a set of guidelines for doctors to aid them in deciding if a patient with foot or ankle pain should have an X-ray to diagnose a possible bone fracture.

X-rays are only required if there is bony pain in the malleolar or midfoot area, and any one of the following:

• Bone tenderness along the distal 6cm of the posterior edge of the tibia or tip of the medial malleolus
• Bone tenderness along the distal 6cm of the posterior edge of the fibula or tip of the lateral malleolus
• Bone tenderness at the base of the fifth metatarsal
• Bone tenderness at the navicular bone
• An inability to bear weight both immediately and in the emergency department for four steps

Certain groups are excluded, in particular children (under the age of 18), pregnant women, and those with diminished ability to follow the test.

Application of the guideline reduces patient waiting time, avoids inappropriate X-ray exposure, improves accuracy of the clinical examination, and reduces health care expenditures on unnecessary X-rays of the ankle and foot without compromising the quality of care.