Advanced imaging of the ankle with MR or CT arthrography can be useful in patients with recurrent ankle pain after older ankle injuries. In such patients, impingement due to scar tissue or hypertrophied synovium may be the cause of pain. While x-rays are usually sufficient to aid in the diagnosis of anterior impingement (bone spurs), when there is suspected anterolateral or posterior impingement, CT or MR arthrography can assist in identifying patients who may benefit from arthroscopic treatment (debridement).
MRI can differentiate among many other causes of ankle pain in the setting of normal x-rays.
Sinus tarsi syndrome can result from trauma or rheumatoid like diseases. Localization of pain may be difficult to establish. Tearing or synovitis of the subtalar ligaments may lead to pain or instability. The following example demonstrates sinus tarsi syndrome:
Osteochondral lesions of the talar dome may or may not be evident on x-rays. These lesions may present in the acute setting, but are more commonly detected later, after a remote trauma with persistent ankle pain. MRI can accurately detect and stage these lesions. Unstable lesions requiring surgery can be identified with MRI.
Tendonitis or tears of the tendons can also be a cause of chronic ankle pain with negative x-rays. MRI can distinguish between tendonitis and tears requiring surgical repair.
The cases below illustrated several examples.