The thumb bends when shaking: 1, more common in the middle-aged and elderly metacarpophalangeal arthritis, there will be obvious osteophyte degeneration in the metacarpophalangeal joint area, so that when the thumb flexes and extends the hyperplastic bone will stimulate the thumb flexor tendon, and the thumb bends shaking symptoms. 2, also seen in the thumb flexor tendon stenosis tenosynovitis, mainly in the thumb repeated flexion and extension activities, resulting in repeated friction of the tendon sheath, causing If the symptoms are relieved by standardized and strict conservative treatment, the problem is not serious; if the symptoms are not relieved and the prolonged shaking affects normal life, surgery may be required to cure the problem completely.