Give this gear a go, Comfrey.
You can get it at the 'elf food shops.
There's a couple of different sorts, we got some in tube & some in a jar.
The jar is smaller & cheaper than the tube but it is also greasier & seems to work faster.
I've got a dicky knee & it seems to work a treat. :)
Watch out for the greasy sheyet in the jar 'cos if you get it on your hands & rub your eye, you'll have a crook eye for a day. :(