When it's not your time to die
ACL replacement surgery is very common these days, which usually takes
the hamstring tendon, split in half down the middle, together with the
bone it's attached to, and screws it in place of where the ligament
used to be. Tendon and ligament are effectively the same material, but
the former is in a more 'live' state which can regrow and heal,
whereas once it's stopped being pulled by muscles all the time it
stabilises into another more static state.
Our 18 month old Heinz 57 dog did an ACL running through a hedge.
After vet had operated and we got dog back, it was clear that the
"ankle" and "thigh" had been nailed to a board, JC fashion, in the mid
position whilst the ACL was rebuilt and resewn. Dog was fine and
lived another 16 years with no trace of stiffness.