Table 1.

Semi-quantitative histomorphometric scoring system as modified by Svensson, Soslowsky, and Cook

Parameter	Grade 0	Grade 1	Grade 2	Grade 3
Fiber structure, Svenson and Solowsky scores	Normal parallel collagen fibers	Mild changes (< 25% slightly separated fibers)	Moderate changes (25–50% disorganized, separated, and deteriorated fibers)	Marked changes (> 50% disorganized and hyalinized fibers)
Cellularity (aspect), Cook scores	Elongated nuclei and absence of cytosol	Oval nucleus and absence of cytosol	Round nucleus and little cytosol	Round nucleus and abundant cytosol
Vascularity, Svensson score	Few vessels, parallel to the fiber	Slight increase of vessels	Moderate increase of vessels	Marked increase of vessels
Cartilage formation	No cartilage	Isolated cartilage nodules	Moderate cartilage formation (25–50%)	Extensive cartilage formation (> 50%)