Current cell-based strategies for knee cartilage injuries.

Cartilage is frequently damaged and shows little or no capacity for repair. Injuries that extend to the subchondral level show some capacity for repair due to the release of bone marrow derived mesenchymal stem cells. This technique is employed in techniques like the microfracture but they are only appropriate for smaller cartilage defects. Autologous Chondrocyte Implantation (ACI) and Matrix-carried Autologous Chondrocyte Implantation (MACI) are currently used in clinical practice to treat larger full thickness chondral defects in the knee with similar results. MACI does however have a number of advantages including its amenability to be performed arthroscopically or through a more limited approach without requiring arthrotomy. More definitive studies showing the long-term effects of the two cell-based treatments and comparing them are however awaited. There are a small number of studies using mesenchymal stem cells and further in vitro and in vivo studies are needed before this treatment is optimised. This review discussed these treatment options and provides an evidence-based approach to current clinical treatments.