I do second Pigmad's suggestion. Hydrotherapy - controlled, supervised etc. - can be good on some medical grounds.
Charlie had major foot issues two years ago, where he was attacking his back foot. He ended up with no nails on that foot, the toes a bloody, swollen mess; every time they started healing he attacked it again...the problem was severe. The initial problem appeared to be paralysis, or some kind of loss of feeling and some movement, and the problems just escalated when he started attacking the foot. We spent 2-3 moths bandaging the foot daily, and also a couple of weeks halfway through giving him some "modified hydrotherapy" sessions; not full swimming, but holding his back legs unsupported (his rump supported obviously) in some deepish water, encouraging him to paddle his back feet. Within a few days he had got some movement back, some strength, and we finally started getting some separation between his swollen and rather mutilated toes.
Full hydrotherapy could work very well with some pigs, as long as it is done properly.