Table 2.

Pathology of tendon degeneration and staging

Stage	Description	Reference
I	Initial Tendinitis: This is the injury stage, healing is not expected until through stage II.	[75]
II	Tendinosis: Increased fibroblast, endothelial and smooth muscle cell populations. Either healing occurs by this stage or tendon progresses to stage III.	[108]
III	Complete rupture/tear: Defective healing is expected once tendon pathology has progressed to this stage.	[80]
IV	Tendinosis with degeneration: Typical degenerative changes, like disorganization and thinning of collagen fibrils, fatty infiltration, myxoid or hyaline degeneration, calcification and/or chondroid metaplasia.	[77]