Table 1.

Histological grading of implanted scaffold

Histological findings	3	2	1	0
Day 3 scoring criteria
Cellular infiltration (per 40 × field)	> 150 cells	75–150 cells	1–75 cells	0 cells
Degradation	No scaffold present	Some scaffold present	Mostly present	No degradation
Encapsulation	No encapsulation	Minimal encapsulation	Moderate encapsulation	Dense encapsulation
Inflammatory cell aggregation (per 40× field)	0 cells	1–75 cells	75–150 cells	> 150 cells
Day 14 scoring criteria
Cellular infiltration (per 40× field)	> 150 cells	75–150 cells	1–75 cells	0 cells
Connective tissue organization	Highly organized connective tissue present	Moderately organized connective tissue present	Unorganized connective tissue throughout disrupted original scaffold	Original scaffold intact
Degradation	No scaffold present	Some scaffold present	Mostly present	No degradation
Encapsulation	No encapsulation	Minimal encapsulation	Moderate encapsulation	Dense encapsulation
Multinucleated giant cells (per 40× field)	0 cells	1 cell	2–5 cells	> 5 cells
Vascularity (per 40× field)	> 10 vessels	6–10 vessels	2–5 vessels	0–1 vessel
Day 35 scoring criteria
Connective tissue organization	Highly organized connective tissue present	Moderately organized connective tissue present	Unorganized connective tissue throughout disrupted original scaffold	Original scaffold intact
Degradation	No scaffold present	Some scaffold present	Mostly present	No degradation
Encapsulation	No encapsulation	Minimal encapsulation	Moderate encapsulation	Dense encapsulation
Multinucleated giant cells (per 40× field)	0 cells	1 cell	2–5 cells	> 5 cells