[Diagnostic imaging of acute and chronic osteochondral lesions of the talus].
Acute fractures involving the articular surface of the talus run parallel to the surface and are confined to the cartilage and/or the immediate subchondral cancellous bone. Subchondral microfractures ("bone bruises"), osteochondral fractures and solely chondral fractures are different manifestations of impaction injuries that affect the articular surface. This article reviews the radiologic appearance of acute osteochondral lesions of the talus and comments on the role of the noninvasive imaging modalities. Conventional radiography and MRI provide the most relevant information and are widely discussed. A MRI classification is presented emphasizing the distinction between lesions with intact and disrupted cartilage. Osteochondrosis dissecans (OCD) is a chronic osteochondral lesion. It is diagnosed in most cases by conventional radiography. MRI has become a decisive tool in staging the lesions. Intact cartilage and contrast enhancement of the lesions are findings of MRI stage I. Cartilage defects with or without incomplete separation of the fragment, fluid around an undetached fragment, cysts larger than 5 mm in diameter and a dislodged fragment are MRI findings observed in stage II and operative treatment has to be considered.
Bohndorf
K
K
Klinik für Diagnostische Radiologie und Neuroradiologie, Klinikum Augsburg, Postfach 10 19 20, 86009 Augsburg. radiol-klin.augsburg@gmx.de
Imhof
H
H
Schibany
N
N
D016512:Ankle Injuries / Q000175:diagnosis*; D002358:Cartilage, Articular / Q000293:injuries* / Q000473:pathology; D050723:Fractures, Bone / Q000175:diagnosis*; D050724:Fractures, Cartilage; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging; D013628:Talus / Q000293:injuries* / Q000473:pathology; D014057:Tomography, X-Ray Computed