Measurement of stiffness in the metacarpophalangeal joint: circadian variation.

A finger arthrograph has been used to investigate circadian variation of stiffness in the metacarpophalangeal joints of normal subjects. A marked increase in the resistive torques of male and female joints was noted during the early hours of the morning (typically 2 to 3 times the torque found during the afternoon). The amount of energy dissipated by the joint and associated soft tissues also showed a circadian variation, with the highest levels of energy dissipation again occurring during the early hours of the morning (0200-0400).