[Osteochondral lesions of the talus -- indications for MRI with a contrast agent]

This study aims to establish the indication for a pre- and postoperative MRI examination with an intravenous contrast agent in patients with an osteochondral lesion of the talus.

20 patients with an osteochondral lesion of the talus in the different stages according to DiPaola were prospectively examined preoperatively and 6 months postoperatively by an MRI investigation with an i. v. contrast agent. The Weber ankle score was determined pre- and postoperatively. A correlation was calculated between MRI and arthroscopic findings of an osteochondral lesion (Spearman-rho).

There was a significant correlation among the radiological, the MRI and the arthroscopically determined locations. With regard to staging only 12 out of 20 lesions were staged correctly by MRI using arthroscopy as a gold standard. Due to metal artifacts and morphological changes the postoperative MRI could not be used for staging.

A preoperative MRI investigation is indicated in patients with ankle pain of unknown origin, a normal radiograph and a suspected osteochondral lesion of the talus. MRI is not indicated to determine the localization and the stage of an osteochondral lesion. A postoperative MRI is only necessary for the exclusion of a secondary pathology.