Table 4: CT staging system for osteochondral lesions of the talus.

Stage Definition
I Cystic lesion with intact roof
IIA Cystic lesion with communication to talar dome surface
IIB Open articular surface lesion with overlying nondisplaced fragment
III Nondisplaced fragment with lucency
IV Displaced fragment

CT classifcation of OLT - Ferkel RD, Sgaglione NA, DelPizzo W. Arthroscopic treatment of osteochondral lesions of the talus: long-term results. Orthop Trans. 1990; 14:172-8.