Table 2.

The descriptions of criteria used in tibial, femoral, and patellar scoring.

Score	Discoloration	Deformation	Fibrillation, Abrasions, and Lesions
0	none	none	none
1	present	present	fibrillated or abrased surface
2	present *	present *	fibrillated or abrased surface with minor focal lesions
3	present *	present *	deep moderate lesions; damage to the tissue surrounding the lesion
4	present *	present *	large deep lesions with severe damage to large areas of the tissue

Fibrillation and lesion descriptions are as detailed by OARSI (Cook et al. 2010), and based on the Outerbridge classification (Outerbridge, 1961) and Mastbergen modifications (Mastbergen et al., 2006). Discoloration and deformation are the additional criteria for all anatomical sections. The descriptions from lower scores may or may not be preexisting features. For example, there may be fibrillation present for scores 3 and 4. Presence of either discoloration or deformation immediately elicits a score of 1. A * indicates that the discoloration or deformation may be obscured by more severe damage.