The treatment of thumb stiffness and inability to bend voluntarily needs to be decided according to the cause of the disease. The most common causes of thumb stiffness and inability to flex voluntarily include stenosing tenosynovitis, localized trauma to the thumb, rheumatoid arthritis, joint contracture, etc. Common treatments include medication, surgery, and rehabilitation. 1. Stenosing tenosynovitis: the thumb cannot be flexed or extended on its own, or it needs the help of the other hand to be straightened, in this case, it needs to be actively treated with surgery, tendon sheath incision or partial excision surgery. 2. Localized trauma to the thumb: trauma causing fracture, dislocation, and tendon rupture will also make the thumb unable to flex voluntarily. Combine with physical examination and auxiliary examination, such as taking ordinary X-ray film to clarify the diagnosis. Fractures and dislocations need to be restored to a normal anatomical relationship first, followed by splinting and, if necessary, internal fixation surgery. Tendon rupture is fixed with plaster and splint after surgical suture. 3. Rheumatoid arthritis: this disease is related to heredity, immunity, etc., and the thumb is stiff and cannot be bent on its own. Diclofenac sodium, ibuprofen and other anti-inflammatory; leflunomide, hydroxychloroquine and other anti-rheumatic can be given as prescribed by the doctor. 4. Joint contracture: If the metacarpophalangeal joint or interphalangeal joint has been sutured, the soft tissues outside the joint will form a scar, and contracture will occur, which makes the thumb stiff and unable to bend; when the contracture is mild, rehabilitation treatment can be carried out under the guidance of doctor; when the contracture is severe, surgery can be considered to loosen the soft tissues. When the contracture is more severe, consider surgery to release the soft tissue. If the thumb is stiff and cannot bend on its own, go to the surgery department or orthopedic department of the hospital as soon as possible, and don’t do it by yourself, so as not to miss the treatment time.