Pain in a single finger joint may be caused by factors such as osteoarthritis, osteophytes or tenosynovitis. 1. Osteoarthritis: Osteoarthritis is a common joint disease, mainly caused by cumulative strain and tissue degeneration, which can involve the finger joints, knee joints, elbow joints, shoulder joints and other parts of the joints, and is mostly found in the middle-aged and elderly people who are obese and overweight, and the symptoms often appear in the patients are joint pain, swelling, and stiffness. 2. Osteomalacia: Osteomalacia is a disease in which the cartilage, ligaments, intervertebral discs and other tissues constituting the joints degenerate and deteriorate, and bone spurs are formed at the joint edges or the synovium is thickened, etc. Patients may suffer from joint pain and restricted joint activities, etc. It is mostly seen in the middle-aged and the elderly. 3. Tenosynovitis: Tenosynovitis is an inflammation of the tendon sheaths in the joints due to strain, trauma and other reasons, and patients may experience symptoms such as swelling, pain and dysfunction in the affected joints. Single finger joint pain may also be caused by other reasons, it is recommended that patients with this symptom go to the orthopedics, rheumatology and immunology departments of regular hospitals for detailed consultation, and follow the doctor’s instructions for diagnosis and treatment.