Hello, and welcome to the community!
An elevated sed rate could be caused by any number of things! It's generally a marker for inflammation, but not a diagnostic aide. It's possible that either the heart disease and/or the OA are causing it to be elevated as well as, if I'm understanding correctly, surgeries to remove prosthesis - the surgeries alone could be a cause of inflammation. Has he discussed the elevation with his doctor? If so, what are they saying about it? Have the run any other labs?
Please touch back with us and let us know how things are going!