Fig. 1

Cell-based therapies for cartilage defects have evolved through a few generations with various cell sources. Using expanded autologous cells, one cell type can be used, but the cell expansion can take several weeks. Traditionally, autologous chondrocytes were used, but autologous mesenchymal stromal cells (MSCs) derived from several sources, such as bone marrow (BM) adipose tissue (AT), synovium (S) and peripheral blood (PB) are increasingly used. A single-stage cell-based treatment relies on obtaining sufficient cells within the time frame of a single surgery. Options being explored are autologous MSC-rich concentrates, such as a bone marrow concentrate (BMC), or the vascular stromal fraction from adipose tissue (ATVSF) or a combination of rapidly isolated autologous chondrons combined with allogeneic MSCs or an autologous MSC-rich concentrate. An off-the-shelf product that is readily available could consist of expanded allogeneic MSCs or an induced pluripotent stem (iPS) cell line or an embryonic stem cell (ESC) line. ATMSC, adipose tissue-derived mesenchymal stromal cell; BMMSC, bone marrow-derived mesenchymal stromal cell; PBMSC, peripheral blood-derived mesenchymal stromal cell; SMSC, synovium-derived mesenchymal stromal cell