Chondrocytes From Device-Minced Articular Cartilage Show Potent Outgrowth Into Fibrin and Collagen Hydrogels

Abstract

Background: Transplantation of autologous minced cartilage is an established procedure to repair chondral lesions. It relies on the migration of chondrocytes out of cartilage particles into a biomaterial. So far, there is no efficient way to finely mince cartilage. No consensus exists on the nature of the biomaterial to be used to promote chondrocyte migration. Purpose/Hypothesis: This study aimed to investigate the potential clinical use of a custom-made mincing device as well as a possible alternative biomaterial to fibrin glue. The device was tested for its effect on chondrocyte viability and on subsequent chondrocyte migration into either a fibrin or a collagen gel. We hypothesized that device mincing would allow finer cutting and consequently more cell migration and that the gelation mechanism of the collagen biomaterial, which uses the clotting of platelet-rich plasma, would enhance matrix production by outgrown chondrocytes. Study Design: Controlled laboratory study. Methods: Cartilage from 12 patients undergoing knee arthroplasty was taken from the femoral condyles and subsequently either hand minced or device minced. The viability and the degree of outgrowth were quantified with live/dead assay on the generated cartilage particles and on the gels in which these particles were embedded, respectively. Matrix deposition in the biomaterials by the outgrown cells was investigated with histology. Results: The device allowed rapid mincing of the cartilage and produced significantly smaller pieces than hand mincing. The initial chondrocyte viability in cartilage particles dropped by 25% with device mincing as compared with no mincing. However, the viability in hand-minced, device-minced, and unminced samples was no longer different after 7 and 28 days in culture. Outgrowth scores were similar among the 3 groups. Fibrin and collagen biomaterials equally supported chondrocyte outgrowth and survival, but neither promoted matrix deposition after in vitro culture. Conclusion: The outgrowth potential, the viability after 28 days in culture, and the matrix deposition were not different between the mincing techniques and the tested biomaterials, yet device mincing is faster and results in significantly smaller cartilage particles. Clinical Relevance: Device mincing could become the standard method to mince cartilage for second-generation cartilage repair techniques.