After 20+ years of doing it, and all on plates, I would agree that thumbs, wrist shoulder and neck injuries are very prevalent. But, lower joints (knees, hips, ankles) are also taking a beating. I think that standing on a race board for years and years at very high binging angles has got to create additonal wear and stress on those joints wearing them out prematurely. If I look at myself in the mirror, my body and muscles have developed very asymetircally with a dominate or stronger side and a weaker side. As the years progress, MCL, ACL, and miniscus problems are going to manifest and become more problematic, probably to the point of surgery. I think that it is still a very small price to pay for the fun that I have.
Think Snow!