Clearly none of us are medical experts, so you will certainly get much more accurate information from Dr Treacy.
Having said that, here are my amateur thoughts. While spinning is a high activity exercise for the muscles and cardio system, I would not consider it a high intensity exercise for the hips compared to activities like running, high level skiing, or tennis which involve much more impact and torquing, so I have trouble imagining a risk to the device.
Since the rapid and repetitive movements in spinning seem similar to the simulation machines that they use to measure wear in different prosthetic designs, increased metal wear and metal ion debris is the one possible issue that I can see. It will certainly not wear out the prosthesis unless you peddled for a few hundred years, but it might raise your metal ion levels to some degree. If you decide to go hard into spinning, you could easily monitor this by doing a metal ion blood test now, and another one in a number of months to see if spinning affected the blood ion levels. Someone like Dr Treacy could arrange the blood tests, and suggest how long to wait before the second test in order to see if there is a significant change.
Lets hope that you keep your resurfacing for a lifetime!