-OATS (Osteochondral Autologous Transplantation) is where a doctor takes healthy cartilage from a part of the knee that doesn't really need it, and transfers that cartilage to a place where knee has damaged or missing cartilage.

-CARTICEL or ACI is where a culture of cartilage is taken, grown and then grafted onto a place where cartilage is missing. This procedure is highly effective and therefore highly expensive.

-It would be good to get the ACI treatment but I'm afraid I'll have to go for OATS instead.