What does hypothermia do to the skeletal system?

Not easy to answer. I looked up information on this question and there is not a lot of research on it One study, which I copied, found that long-term hypothermia may keep bone cells from building new bone and might break down bone- this study was in the elderly - so short answer is- don't think we really know for sure http://www.sciencedirect.com/science/article/pii/S0014482712003096.