Reference values for metacarpophalangeal joint stiffness in normals.

A new form of microprocessor-controlled arthrograph is described which measures stiffness parameters of the metacarpophalangeal joints of the index, middle, and ring fingers of both hands. The apparatus is simple and quick to use and gives reproducible results. The arthrograph is used to determine the reference limits for stiffness at the middle finger of the right hand in 128 normal subjects. It is found that incorporating information on the subject's finger circumference allows a much improved precision to be achieved, but the precision is not further enhanced by including details of age and sex.