Table 7 Scoring scheme for evaluating severity of TMJ-OA lesions by macroscopic inspection of articular surfaces (modified after [11])

0

normal

smooth articular surface, smooth articular margin, no irregularities

1

mild

slight unevenness of articular surface, presence of small isolated lytic lesions of subchondral bone (pits) affecting less than 25% of the articular surface, articular margin may be locally flattened or slightly thickened, single periarticular osteophytes may be present

2

moderate

more pronounced unevenness of articular surface giving it a bumped appearance, more frequent and/or more profound lytic lesions of subchondral bone affecting 25% to 50% of the articular surface, more pronounced flattening or thickening of articular margins, presence of periarticular osteophytes (at least two features must apply)

3

severe

very pronounced to massive unevenness of articular surface, lytic lesions of subchondral bone affecting more than 50% of the articular surface, markedly irregular articular margin sometimes leading to an abnormal contour of the mandibular fossa and/or the mandibular head that can cause joint incongruity, pronounced periarticular osteophytosis, changes can lead to partial or complete ankylosis of the TMJ (at least two features must apply)