The clinical and radiological importance of extraarticular contrast material leakage into adjacent synovial compartments on ankle MR arthrography in patients with OCD and anterolateral impingement.

PURPOSE: To evaluate the tibiotalar joint capacity and the localisation, frequency and amount of extravasation in patients with extraarticular contrast material leakage into adjacent synovial compartments on ankle magnetic resonance (MR) arthrography.

MATERIALS AND METHODS: Sites of extravasation were determined in the ankle MR arthrograms of 69 patients. Thirty-four patients without extraarticular contrast material leakage into locations unrelated to the injection path were included as a control group. Volumetric measurements of extraarticular contrast material leakage and the tibiotalar joint capacity were performed on a three dimensional (3D) volume measurement workstation.

RESULTS: Extravasation of contrast material occurred through the anterior, posterior, and anterolateral recesses of the tibiotalar joint. The most common site of extravasation was along the flexor hallucis longus tendon synovium (24.6%). The amount of extravasation was significantly higher in patients with ankle osteochondritis dissecans (OCD) than in patients with a different diagnosis (p=0.039). Loose bodies were detected in all OCD's patients with insufficient tibiotalar joint distention.

CONCLUSIONS: Connections between the ankle joint and neighboring synovial compartments can decrease the diagnostic value of ankle MR arthrography examinations due to inadequate joint distention. Large injection volumes should be used for ankle MR arthrography of patients with OCD (especially OCD's patients with loose body) and impingement syndrome.