Table 1.

Characteristics of cartilage tissue specimens used for in vitro experiments.

Donor	Age range	Collins grade#	Cartilage characteristics
1	18–25	0	Normal
2	46–50	1	Minor fibrillation
3*	66–70	1	Minor fibrillation
4	71–75	1	Minor fibrillation
5	51–55	2	Fibrillation + fissures
6	61–65	2	Fibrillation + fissures
7	71–75	2	Fibrillation + fissures
8	66–70	3	≤30% full-thickness erosion
9	66–70	3	≤30% full-thickness erosion
10	56–60	4	≥30% full-thickness erosion

^*Femoral cartilage was obtained from specimen #3. Tibial cartilage was obtained from all other donors.