I have a crossbred gilt that is 175# and has swollen back hocks. What would of caused this and how do I treat it?

We had this problem with a duroc barrow a couple of years ago. With ours, it was caused by the pig growing to fast and too big for his frame causing early arthritis in the hocks it was also probably due to faulty genetics too. Not a cure, but the best thing to do is to keep the hog moving and use equine liniment to sooth pain. A few bantamine shots won’t hurt either, but only use as directed by a veterinarian. Hope this is helpful.