Table 3.

Griffith MRI classification of talar dome osteochondral lesions

Grade	Description
1a	Bone marrow change (edema, cystic change) with no collapse of subchondral bone area, no osteochondral junction separation and intact cartilage
1b	Similar to grade 1a though with cartilage fracture
2a	Variable collapse of subchondral bone area with osteochondral separation though intact cartilage
2b	Similar to grade 2a though with cartilage fracture. This is an unstable lesion with level of instability related to extent of cartilage fracture
3a	Variable collapse of subchondral bone area with no osteochondral separation + / − variable cartilage hypertrophy
3b	Similar to grade 3a though with cartilage fracture
4a	Separation within or at edge of bone component with intact overlying cartilage
4b	Similar to grade 4a though with cartilage fracture. This is an unstable lesion with level of instability related to extent of cartilage fracture
5	Complete detachment of osteochondral lesion. This is an unstable lesion