Hello NC spinner,
I would be very surprised if your husband’s suspected osteomyelitis is due to his dialysis-treatments because, when I suffered from “it”, it was due to a bone-infection on a fractured ankle-bone which was so very tiny, that the fact it was still broken and infected was not detected through repeated x-rays and other check-ups.
Please check-up further with a very very experienced orthopaedic surgeon/doctor to have another look at x-rays (if I remember well, one x-ray was done by using a very special light?) etc. and please check up further a.s.a.p., because when I suffered from “it” so many years ago, I was finally operated on by a very clever surgeon who told me after this emergency-operation that there was a tiny infected bone at my ankle-site which needed to be urgently "cleaned" from the bone-infection etc. and after this operation and another three months in plaster and many lots of antibiotics I was finally cleared and touch wood it may stay like this because the whole experience was quite a nightmare and had it not been sorted out so quickly, I could even have lost the use of my ankle …
Good luck and best wishes from Kristina.
P.S. I have tried to explain this experience in my own non-medical way as best as is possible and do hope it is understandable ... and please hurry ...