Figure 1.
Cartilage regeneration techniques. a | A full-thickness focal chondral lesion. b | The lesion is debrided to ensure healthy, stable margins for integration of the host tissue with the neotissue. c | Microfracture. Channels are created using a 45° awl, spaced 3–4 mm apart, and 3–4 mm deep to penetrate the subchondral bone, allowing MSCs to migrate from the marrow to the cartilage defect. d | ACI. The debrided lesion is filled with 12–48 million autologous chondrocytes and covered with a periosteal flap or mixed collagen type I and type III membrane. e | MACI. The autologous chondrocyte population is expanded in vitro and then seeded for 3 days onto an absorbable 3D (collagen types I and III or hyaluronic acid) matrix prior to implantation. The cell-seeded scaffold is then secured into the lesion with fibrin glue. Abbreviations: ACI, autologous chondrocyte implantation; MACI, matrix-assisted autologous chondrocyte implantation; MSCs, mesenchymal stem cells.