The locked metacarpophalangeal joint: diagnosis and treatment.

The locked metacarpophalangeal joint of a finger is an unusual condition frequently confused with a "trigger finger." The causes can be classified into degenerative and spontaneous groups. Ten cases are presented. The cause of locking of one patient in the degenerative group was gouty arthritis, a cause not previously reported in the literature. Although surgery is usually necessary, joint mobility was restored in 30% of the cases by distending the joint capsule with an intraarticular injection of a local anesthetic followed by gentle manipulation. In addition to routine x-ray films, arthrotomography was found to be a useful diagnostic technique in determining the cause of locking.