It's fixable, but could take some work...
If you find a plastic welder (PLast-struct plastic welder is my suggestion) at a hobby shop, you could fuse the two parts of the pin together. They're a styrene type plastic and fuse using those plastic welders. The key is getting the pin out of the thigh...
Let it sit a good 48 hours to set, and it should be sturdy and a solid piece of plastic again (the welder actually liquifies the plastic and the two halves should fuse together in a "welded" single piece).
I know it sounds like a lotta work, and it can be a pain in the ass for sure, but considering the figure... thought maybe you'd be interested in giving it a try.
Also it shouldn't melt the plastic of the leg itself so there SHOULDN'T be any worries there of it fusing to the pin or something. It doesn't work on PVC type plastics that I've ever encountered.