Meniscal transplantation is in the works. It's not done by all surgeons but it's being studied by some. There are many questions left to answer before using this operation on a routine basis.

For example how much meniscus is really needed? What's the best way to prepare donated tissue? How should it be put into the knee? How long does it last? What problems come up soon after the operation compared to years later?

Right now this method of meniscal "repair" is used in young patients who have already had the entire meniscus taken out. Pain and joint degeneration are the basic criteria for this treatment method. There's about a 60 percent success rate. This means about 40 percent (four out of 10) of patients have a failed transplantation.