The study focuses on erosive osteoarthritis of the hands, a condition that causes joint damage and pain in the fingers. This particular form of arthritis is characterized by the breakdown of joint tissue and can significantly impact daily activities. The research aims to evaluate the effectiveness of a medication called methotrexate in treating this condition when other standard treatments have not worked well enough.

The treatment involves weekly injections of methotrexate under the skin, along with folic acid tablets to help manage potential side effects. Some participants will receive sodium chloride solution (salt water) injections instead of methotrexate. The study will last for 52 weeks, during which participants will receive regular medical check-ups to monitor their condition.

Throughout the study, doctors will track changes in the hand joints using special imaging techniques to see if the medication helps prevent further joint damage. This research is particularly important for people who continue to experience hand pain and difficulty with daily tasks despite trying other treatments for their arthritis.