Purpose: To evaluate if the degree of chondral fragmentation affected extracellular matrix (ECM) production in cartilage fragment autograft implantation in vitro. Methods: Cartilage was taken from 5 donors undergoing total hip replacement (mean age, 65.6 years; standard deviation [SD], 3). The cartilage was minced to obtain 4 groups with different fragment sizes: (1) "fish scale" (diameter, 8 mm; thickness, 0.3 mm), (2) cubes with 2-mm sides, (3) cubes with 1-mm sides, and (4) cartilage paste (< 0.3 mm). The cultures were maintained in chondrogenic medium for 6 weeks. Biochemically, a proteoglycan (PG):DNA ratio was calculated as the best approximation of ECM production per cell. The ratio between PG released in the culture medium and the PG in the neocartilage (PGrel:PG) was used as a matrix stability index. Histologically, the slides were stained with safranin O fast green and collagen type II immunostaining. The titration of safranin Oepositive cells and the Bern score were calculated. Results: Regarding the PG:DNA ratio, group 4 performed significantly better than groups 1 (P = .001) and 3 (P = .02), whereas group 2 performed better than group 1 (P = .03). No significant difference was found regarding the PGrel:PG ratio and safranin Oepositive cells. Regarding the Bern score, group 4 performed significantly better than groups 1 (P = .02), 2 (P = .04), and 3 (P = .03). Conclusions: We conclude that human cartilage fragmentation significantly affects ECM production in vitro. Increased fragmentation enhances ECM production.
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