Two types of osteoarthritis exist. Idiopathic osteoarthritis, which has no known cause. Idiopathic osteoarthritis may affect just one or two joints or it may affect three or more joints. Secondary osteoarthritis, which is caused by an underlying condition. The underlying condition may be joint injury, rheumatoid arthritis or other joint conditions, or another medical condition (e.g., obesity).
Symptoms, findings from a physical exam, blood tests and x-rays all help distinguish between rheumatoid arthritis and osteoarthritis. As for treatment, pain medication and other pain management techniques will help with both conditions. However, drugs that are specifically for rheumatoid arthritis, such as biologic drugs, will have no effect on osteoarthritis.
The Bottom Line
It is possible to only have osteoarthritis or rheumatoid arthritis, but it is also possible to have both conditions at the same time.
Patient information. Osteoarthritis symptoms and diagnosis. UpToDate. Kalunian KC et al. September 2009.