Anterolateral compartment of the ankle in the lateral impingement syndrome: appearance on CT arthrography.

OBJECTIVE: This article describes the appearance of the anterolateral recess of the posttraumatic ankle on CT arthrography and clearly shows the benefit of this technique in the diagnosis of soft-tissue impingement. MATERIALS AND METHODS: The study was carried out on 44 patients examined by CT arthrography and arthroscopy for chronic, posttraumatic ankle pain. The analysis principally concerned the lateral compartment--in particular, the synovial regularity and the cartilage of the talar dome. RESULTS: Four CT patterns were identified: type 0, uniform filling of the recess with clear limits; type I, intraarticular linear structure outlined by contrast agent; type II, nodular formation in the lateral groove; and type III, irregular appearance of the edges of the lateral groove. Ninety-one percent (10/11) of type II patterns were characterized as meniscoid lesions by arthroscopic examination, 100% (14/14) of type III patterns corresponded to an abundant fibrous reaction, and arthroscopic findings were normal for 100% (2/2) of type 0 patterns and 88% (15/17) of type I patterns. The latter was thus considered as a normal variant outlining the accessory anterior inferior tibiofibular ligament. Type II and III lesions were statistically associated (p = .001) with a chondropathy when time from initial trauma was greater than 22 months. CONCLUSION: CT arthrography provides evidence of anterolateral soft-tissue impingement--in particular, in type II or III patterns. These lesions are statistically associated with a chondropathy.