Metacarpophalangeal contracture is a condition whose cause has not yet been studied, with a slow onset, mainly invading the metacarpal tendon membrane and pathological changes of longitudinal fibrous connective tissue hyperplasia, followed by flexion contracture. The majority of patients are male (about 90%), with 8-10 times more males than females. The most affected fingers are the ring finger, with the little finger taking second place, and the incidence of the middle, index and thumb decreasing in order. About 40% of cases have bilateral onset. The onset of metacarpophalangeal contracture is generally slow, lasting several years or more than a decade, but it can also progress rapidly within a few months; sometimes the lesion stops and then progresses again, and most patients do not experience any discomfort, but find that the fingers are flexion contracted and cannot be straightened before they are seen. These nodules gradually form longitudinal cord-like masses and contract, or they thicken the adjacent skin and cause a transverse fold of skin to appear at the distal transverse palm line. The deeper layers of the skin are connected to the underlying tendinous tissue in a hard mass with indistinct borders and no obvious pressure pain, followed by contracture of the metacarpophalangeal and proximal interphalangeal joints.