The cause of thumb joint rattling and pain may be joint strain, muscle strain or tenosynovitis. 1. Joint strain: long-term over-activity of the thumb may cause chronic damage to the soft tissues around the joint and the joint capsule, and the thumb will rattle and hurt when moving. 2. Muscle strain: overstretching and contraction of the thumb muscle, muscle damage, thumb activity will also have a loud noise and pain. 3. Tenosynovitis: due to the influence of cold and excessive activities, the tendon sheath of the thumb will have aseptic inflammation, which will lead to the restriction of the thumb activities, pain and sometimes rattling sound when the thumb is moving. There may be other reasons for the thumb joint to rattle and hurt, such as rheumatoid arthritis, etc. You should go to the regular hospital in time, and the doctor will determine the specific cause of the disease according to the symptoms, signs and auxiliary examination.