Table 1.

Eaton and Littler classification apud Martin-Ferrero et al.²

Stage	Radiological criteria – Eaton and Littler
I	Normal joint contours; the interlining articulate may be widened secondary to laxity or joint effusion
II	Slight narrowing of the interlining articulate; joint debris and osteophytes <2 mm Normal ST joint
III	Marked degenerative changes with no interlining articulate, geodes, osteophytes, and sclerosis >2 mm; variable degrees of subluxation; normal ST joint
IV	Similar to stage III but with degenerative changes of the ST joint