Osteochondral allografts or autografts

Another way to patch up cartilage is to take a plug- usually of both bone and cartilage- from either a tissue bank (cadaver) source or from another area in the knee.
There are problems with both of these donors, however. The tissue bank solution is appealing- until you read about disease transmission, including death, from tissue banks. The most celebrated incident occurred in St Cloud Minn a few years ago, and it could happen again. Only this year (2005) did the government start monitoring these tissue banks- and that effort is not problem free.
The other source of these plugs could be your own knee- using an area on the periphery. But for very large defects it is hard to rob Peter to pay Paul.

New Efforts to restore cartilage

Check out www.cartilix.com to look at a new startup in the field.