ok - your Wikipedia reference-linkmeniscus tear has been sorted surgically and won't grow back. the difference between that and your acl is vascularity. if you tear your acl and a is still attached to b by a few threads then it should regrow because of the vascularity (blood vessels). BUT it may not have the same strenght or lenght, potentially making your knee unstable. not necessarily in straight line stuff, but in rotational activities.

this is the dilemma of braces. they'll give you false support by making the muscles around the knee more active, but as a ridgid structure can't protect the rotatory componant (unless they drill into your bone!)

perhaps reattaching is the wrong word, unless the tear is at the bone/tendon junction of the acl then it probably won't, but with the right rehab protocol to improve rotatory control, hammys and gluts then you may not require to rest and depend on the tensegrity of your cruiciate.

don't get it reconstructed unless it's knackered (gives way, blows up type thing). but do get going on rotatory control, plyometrics not just booting a ball around.

cheers

sixphysio