I know I am belabouring the point here, but minor stress fractures.... My understanding is that when a bone heals, it actually calcifies more intensely along the line of a fracture than it does in the rest of the bone. But these things, even though they may be calcified, lead to arthritis and rheumatism, as you say, and all these other issues.
On April 26th, 2007. See this statement in context.