LOCALISATION OF OSTEOCHONDRAL LESIONS OF THE TALAR DOME

Abstract

Introduction: Osteochondral lesions (OCL) of the talar dome are defects of the cartilaginous surface and underlying bone of the superior articular surface of the talus. Their natural history is uncertain, but the association with residual, debilitating ankle pain is strong. Literature describes OCL’s as occurring anterolaterally or posteromedially, with associated localising symptoms. Early diagnosis of OCL’s may be important in preventing progression. The aim of this study was to investigate the value of clinical findings when compared to MRI scanning.

Materials and Methods: Patients with reported OCL’s of the talar dome on MRI were asked to indicate the location of their ankle pain. Subsequently they were physically examined to identify the area of maximum tenderness. Direct visual measures were taken of these sites, using modified anthropometry. The patient, examiner and person measuring were blind to the MRI scan. The lesion on MRI was then measured and locations compared for any correlation, distance and association.

Results: A series of eighteen OCL’s were studied. The strongest correlation was between the subject and the examiner in the axial plane (medial/lateral). The weakest was between MRI and clinical locations in the axial plane. Overall, the greatest difference between locations was between clinical examination and MRI. Euclidean distances showed that clinical predictions of lesion site were only reliable to within approximately 5cm.

Discussion and conclusion: Although there was a correlation between some locations, measure reliability negated this as the distances between sites represented the maximal distances within the ankle joint. We suggest that OCL of the talar dome result in pain that is poorly localised with respect to the site of the lesion. Suspicion of OCL must remain high in cases of un-resolving ankle pain, irrespective of specific clinical findings and early evaluation with the use of MRI scanning is justified.