Meniscal tears can heal, but rarely.
If the outer 1/3 meniscus is torn, it has a good blood supply and can heal, but it is usually separated where torn. The two edges need to be re-approximated and fastened together. If the inner 2/3 of the meniscus is torn, there is no blood supply so no healing can take place. These central types of injuries are usually treated by removing the damaged part.