Effects of Micronized Cartilage Matrix on Cartilage Repair in Osteochondral Lesions of the Talus

Background: The repair of osteochondral lesions remains a challenge due to its poor vascularity and limited healing potential. Micronized cartilage matrix (MCM) is dehydrated, decellularized, micronized allogeneic cartilage matrix that contains the components of native articular tissue and is hypothesized to serve as a scaffold for the formation of hyaline-like tissue. Our objective was to demonstrate in vitro that the use of MCM combined with mesenchymal stem cells (MSCs) can lead to the formation of hyaline-like cartilage tissue in a single-stage treatment model. Design: In group 1 (no wash), 250 µL MCM was reconstituted in 150 µL Dulbecco’s phosphate-buffered saline (DPBS) for 5 minutes. Group 2 (saline wash) included 250 µL MCM washed in 20 mL DPBS for 30 minutes, then aspirated to remove all DPBS and reconstituted in 150 µL DPBS. Group 3 (serum wash): 250µL MCM washed in 20 mL DPBS for 30 minutes, then aspirated and reconstituted in 150 µL fetal bovine serum. Each group was then added to 50 µL solution of MSC suspended in DPBS at a concentration of 1.2 × 10⁶ cells/350 µL. After 3 weeks, the defects were extracted and sectioned to perform viability and histologic analyses. Results: Stem cells without rehydration of the MCM showed almost no viability whereas near complete cell viability was seen after rehydration with serum or saline solution, ultimately leading to chondrogenic differentiation and adhesion to the MCM particles. Conclusion: We have shown in this proof-of-concept in vitro study that MCM can serve as a scaffold for the growth of cartilage tissue for the treatment of osteochondral lesions.