Cartilage repair - ACI

Articular cartilage has a poor potential to heal by itself as it has no native blood supply. Autologus chondrocyte implantation (ACI) is a cell therapy involving a two stage procedure to repair isolated (not widespread) cartilage defects. Initially an arthroscopic sample of you bone marrow or cartilage is taken and sent to the laboratory to culture and grow cells (chondrocytes and/or mesenchymal stem cells). At a second operation involving an open procedure these cells are implanted into the bearing surface defect using a patch of synthetic collagen to cover the defect.

The surgery for the second stage can take around an hour to perform and is often combined with other repair or reconstructive surgery around the knee. It is often very painful at first and you are in hospital for 3-5 days. The rehabilitation is prolonged with physiotherapy for 6 months or more and most patients reach the peak/maximum recovery by around 18 months post op. 
Cartilage lesion with central osteophyte

Healed ACI