Current concept review: osteochondral lesions of the talus.

Osteochondral lesion of the talus (OLT) is a broad term used to describe an injury or abnormality of the talar articular cartilage and adjacent bone. Historically, a variety of terms have been used to refer to this clinical entity including osteochondritis dissecans, osteochondral fracture, and osteochondral defect. Currently, six characteristics are used to categorize a particular lesion (Table 2). An OLT can be described as chondral (cartilage only), chondral-subchondral (cartilage and bone), subchondral (intact overlying cartilage), or cystic. Lesions can then be subdivided as stable or unstable and non-displaced or displaced. The stability of a lesion can be assessed directly with arthroscopy or indirectly with MRI using DeSmet’s criteria.6 A lesion can also be categorized by its location on the articular surface of the talus as medial, lateral, or central with added subdivisions into anterior, central, or posterior as advocated by some authors.82 An additional description of identifying whether the lesion is contained or uncontained (shoulder) may also be included. Finally, although no accepted definition of lesion size exists, OLTs can generally be considered as either small or large based on their cross-sectional area or greatest diameter (area greater than or less than 1.5 cm2 or diameter greater than or less than 15 mm). Although these characteristics provide a scheme to classify OLTs and to select a therapeutic modality, they do not reliably predict the outcome of treatment. While the exact incidence of symptomatic OLTs is unknown, they are quite prevalent and are a significant