Kouwenhoven, Jan-Willem M.

Objective: To investigate the preclinical feasibility of using bio-airbrush technology for the fully arthroscopic treatment of cartilage defects with a combination of cells and biomaterials. Design: A combination of in vitro , ex vivo , and cadaveric in situ experiments was performed, to evaluate the preclinical feasibility of using bio-airbrush technology for cartilage repair. Cartilage matrix production after airbrushing cells was evaluated. Subsequently, the influence of different spray parameters on successful defect fill was studied. Finally, the surgical feasibility of using bio-airbrush technology was evaluated in situ in cadaveric knees. Results: The most important findings of the presented study are that the matrix producing capacity of the cells was not hampered by airbrushing, air pressure and defect location were important parameters to consider, and using the bio-airbrush was found to be surgically feasible in a CO 2 -insufflated arthroscopic procedure in cadaveric knees. Conclusions: Bio-airbrush using CO 2 arthroscopy would facilitate fully arthroscopic application of (cell laden) two-component in situ gelating biomaterials to cartilage defects, as a treatment for cartilage repair. This would shift the conventional procedures, which are commonly performed using a (mini-)arthrotomy, toward arthroscopy. Impact Statement This study shows that a bio-airbrush can be a clinically feasible instrument for the use in cell transplantations to repair knee cartilage defects. This technology would enable a shift from cartilage repair procedures, which are mostly performed using an arthrotomy, toward a fully arthoscopic approach. In addition, the technology presented could possibly be translated to other fields of research where controlled in situ deposition of cells is required, such as treatment of burn wounds/ulcers/others. Our research has shown that the use of an airbrush is safe, without harming cell viability and performance.

Purpose: To test the technical aspects and feasibility of seeding a combination of meniscus cells isolated from a rapid digestion protocol and mesenchymal stromal cells (MSCs) (20:80 ratio) into a meniscus scaffold for the development of a one-stage arthroscopic procedure for meniscus regeneration. Methods: A cadaveric study was performed using nine fresh frozen human cadaveric knee joints. Two different arthroscopic cell-seeding methods were applied to the Collagen Meniscus Implant (CMI ® ) as carrier scaffold: either (1) seeding before arthroscopic surgical implantation of the scaffold or (2) after implantation of the scaffold. The cells were injected inside the scaffold, using fast green-stained fibrin glue as carrier, to macroscopically visualize the amount of fibrin glue. Macroscopic pictures and confocal microscopy analyses were used to determine cell distribution and viability. In addition, the DNA content in the cell-seeded scaffold was determined. In addition, different concentrations of Liberase were examined to find the optimal concentration for rapid digestion of meniscus tissue. Results: Macroscopically, seeding before implantation showed a better distribution of fast green-stained fibrin glue carrier than seeding the scaffold before surgical implantation. In addition, it resulted in significantly more cells and a better cell distribution compared with seeding the scaffold after arthroscopic implantation. Both seeding methods did not affect cell viability. After rapid digestion, 0.0125% Liberase resulted in the highest cell isolation efficiency. Conclusions: This study demonstrates that living human meniscus cells can be isolated efficiently, combined with MSCs in 20:80 ratio, and uniformly delivered into a currently available meniscus scaffold. This scaffold can then be arthroscopically implanted, creating a one-stage solution for partial meniscal deficiency. Impact Statement Meniscus injury remains the most common indication for orthopedic surgery, but loss of functioning meniscus tissue is strongly correlated with development of early osteoarthritis. However, current clinical options for tissue engineering of the meniscus are limited. This study demonstrates the feasibility of combining human meniscus cells with mesenchymal stromal cells to enhance a meniscus scaffold for meniscus regeneration in a one-stage solution for partial meniscal deficiency.