No Difference in Chondrocyte Viability Using Manual Versus Custom-Cutting Technique for Matrix-Induced Autologous Chondrocyte Implantation.

Background: Matrix-induced autologous chondrocyte implantation (MACI) was developed for knee cartilage restoration involving seeding autologous chondrocytes onto a collagen membrane. Maintaining chondrocyte viability and achieving proper membrane size and contour are crucial for successful outcomes. Scissor cutting (Sc) has traditionally been used to shape the membrane, but recently, custom cutting (CC) have gained popularity for their enhanced preparation efficiency.

Purpose: To determine the difference in chondrocyte viability using the Sc versus CC methods.

Study design: Controlled laboratory study.

Methods: Using Sc and CC methods, 15 mm-diameter circular specimens were cut from 5 residual membranes. Membranes were stained, and confocal microscopy was used to visualize live/dead cells. Three zones were defined: the impact zone (the outermost zone at the cut edge), the central zone (the least manipulated zone), and the adjacent zone (the intermediate zone between the central and impact zones). For each circular specimen, the following measurements were recorded: the dimension of the impact zone, cell viability (percentage of live cells among total) for each zone, and the total number of cells within each zone (as cell density ×10⁵/cm²).

Results: The width of the impact zone (mean ± standard error) was 355 ± 31 μm and 342 ± 24 μm for CC and Sc, respectively, and the impact zone occupied approximately 10% of the specimen. With both cutting techniques, cell viability was significantly lower in the impact zone (mean ± standard error: CC, 36.42% ± 3.85%; Sc, 40.94% ± 2.85%) compared with the adjacent zone (CC, 77.69% ± 2.97%; Sc, 74.17% ± 2.8%). The cell density from all zones varied from 5.84 ± 0.26 to 6.49 ± 0.34 × 10⁵/cm², with no significant difference in cell viability in the impact zones between the cutting methods.

Conclusion: Both cutting techniques led to a significant reduction in cell viability in the impact zone compared with other zones of the MACI specimen. There was no significant difference in chondrocyte viability or cell density for membranes cut by Sc or CC.

Clinical relevance: This evaluation of the newly introduced CC method on the chondrocyte viability of the MACI membrane will enable surgeons to make a more informed decision regarding cutting techniques.