Table 3 Pathogenetic models proposed for calcific tendinopathy (CT) of rotator cuff tendons (RCTs) and insertional CT of the Achilles tendon.
Stage | Cells | Extracellular matrix | Blood vessels | Inflammatory cells |
|---|---|---|---|---|
CT model proposed by Uhthoff [28] for the rotator cuff: | ||||
Pre-calcific stage | Chondrocyte-like cells | Fibrocartilaginous metaplasia, presence of calcium crystals collected into matrix vesicles | None | None |
Calcific stage: | Â | Â | Â | Â |
Formative phase | Chondrocyte-like cells | Multifocal calcific deposits separated by fibrocollagenous tissue or fibrocartilage | None | None |
Resting phase | Chondrocyte-like cells | Fibrocollagenous tissue borders the foci of calcification | None | None |
Resorptive phase | Chondrocyte-like cells | Deposits of a thick, creamy, toothpaste-like material under pressure appear | Vascular channels near the calcific deposits | Macrophages and multinucleated giant cells cathepsin K-positive [22] |
Post-calcific stage | Fibroblast | Granulation tissue, deposition of type III collagen | Capillaries surround the calcific deposits | Multinucleated giant cells [22] |
Model proposed by Benjamin [34] for insertional CT of Achilles tendon: | ||||
Early stage | Chondrocytes and fibrocartilage cells | Fibrocartilage metaplasia | None | None |
Second stage | Few chondrocytes | Erosion of calcaneal cartilage. Fibrocartilage metaplasia of tendon matrix. | Blood vessels invade the calcaneal fibrocartilage | None |
Bony spur formation | Few fibrocartilage cells | The original cartilage has disappeared | New bone is deposited around the blood vessels | None |