My Mom had to have her right knee replaced again because the inner piece separated and put the rest of her knee at risk of shattering (or something along those lines).
Surgery started at 1:30 and finished about 4:30. That's the only update I have for now. Dr. P said she'd be on her way to recovery in about 20 minutes (at that point). Recovery typically takes an hour - I think last time it took about 2 hours since she doesn't react well to the anesthesia.
I'll try to post updates as they come - or if I can get her Facebook password I'll post updates there too.