Arthroscopically and manually minced cartilage demonstrates lower cell viability and lower proteoglycan deposition compared to isolated chondrons and chondrocytes

OBJECTIVE: Autologous minced cartilage offers a single-stage, low-cost alternative to cell therapies for treatment of chondral defects. It is often derived from debrided defects or loose bodies, then minced for reimplantation. However, there is a paucity of knowledge on how mincing cartilage impacts viability and extracellular matrix deposition compared to quality-controlled cell therapies. The purpose is therefore to better characterize minced cartilage by comparing different mincing techniques to isolated cells.

METHODS: Cartilage samples were obtained from fresh human osteochondral allografts (JRF Ortho) and divided into: chondral allograft biopsy (control), manually minced cartilage, arthroscopically minced cartilage, isolated chondrons, and isolated chondrocytes. Samples were embedded in fibrin gels and cultured for 28 days. Staining for viability and histology for collagen and proteoglycan components were performed. Cartilage samples derived from debrided defects or loose bodies were evaluated for sulphated glycosaminoglycans (sGAGs), DNA, and wet weight.

RESULTS: At 28 days, viability of chondrons (93.7 ± 2.9%), chondrocytes (94 ± 22%) and manually minced cartilage (79.8 ± 16.2%) were significantly higher than arthroscopically minced cartilage (56.6 ± 15.4%). Over time, isolated cells showed proteoglycan and type II collagen deposition, while minced cartilage groups showed reduced proteoglycan content on histology. Clinical cartilage samples varied >10-fold in wet weight, total DNA, sGAGs/weight, and DNA/weight.

CONCLUSION: This study showed isolated cells have consistently high viability and deposit more proteoglycans over time compared to both minced cartilage groups. Samples typically used for clinical application of minced cartilage can vary over 10-fold in cellularity and proteoglycan content. As consequences for treatment effect are unknown, implementation in clinical practice without quality regulation is not recommended.