The most common causes of pain in the first joint of the middle finger are trauma, osteoarthritis, tenosynovitis and so on. 1. Trauma: if the patient’s middle finger has been hit by the outside, it is easy to cause local muscle and ligament damage, and then the first joint pain occurs. 2. Osteoarthritis: Osteoarthritis can occur easily when bone cells are damaged due to various reasons, which can be manifested as degenerative changes of articular cartilage as well as secondary osteomalacia, and usually results in pain, swelling, and stiffness of the finger joints. 3. Tenosynovitis: If the patient repeatedly carries out the activities of the first joint for a long time, the long-term chronic strain will easily induce tenosynovitis, which in turn will show the pain, stiffness, and activity limitation of the joint. Causes of pain in the first joint of the middle finger are many, and may also be related to osteophytes, rheumatoid arthritis, gout and other factors, if the symptoms continue to be unrelieved, it is recommended to go to the hospital in a timely manner to find out the cause of the disease, and targeted treatment by the doctor.