There is no absolute contraindication with placing any implant material in the body with rheumatoid arthritis. But because it is likely you are on some form of immunosuppression agent, there are increased risks of infection. How much increase can be debated. In my experience with rheumatoid patients and chin augmentation, most have opted for a sliding genioplasty to eliminate all of those potential implant risks.
It's probably best to get clearance from your rheumatologist and be off any type of medications that can affect your healing process prior to the surgery.