Locking of the metacarpophalangeal joint of the thumb

摘要: We clinically examined the hands of twenty-three patients and experimented with amputation specimens to clarify characteristic features pathomechanism locking metacarpophalangeal joint thumb. In all had resulted from forced hyperextension Every injured thumb showed a mild deformity joint, having become fixed. Manual reduction was successful in seven patients, but other sixteen required open reduction, during which we found that proximal palmar ligament ruptured transversely its distal part riding over volar prominence radial condyle metacarpal together accessory collateral ligament. These dislocated parts formed constricting bundle on surface prevented closed reduction. The released by cutting constricted bundle. Our description this mechanism is supported experimental evidence obtained examining specimens.