I think this is a problem that your primary care physician
can find a solution to. It may be that the hormonal changes that are occurring the week before your period is making you more sensitive to pain, or allowing more pain producing hormones to be produced. Either way, you perceive it as your arthritis
getting worse. I usually recommend scheduling Acetaminophen (Tylenol) throughout the day so that you stay ahead of the pain from osteoarthritis. Near the time of your period, you may respond better to non-steroidal anti-inflammatory drugs (NSAIDS). You may not be responding to ibuprofen because you are not taking enough. You should talk to your doctor
about what the best dose is right for your situation.
I suggest that you schedule an appointment with your primary care physician. He or she can discuss you symptoms and detail and perform a thorough musculoskeletal physical exam. From there, you can discuss treatments. I think you doctor will likely initially recommend NSAIDs like ibuprofen for the pain you get right around your period, but you may need a prescription strength. In addition, you may need to consider using an oral contraceptive which can help regulate these hormones that may be playing a role.