Osteoarthritis of the hand: longitudinal studies.

Evaluation of the osteoarthritic grades of the hands of 478 participants of the ongoing Baltimore Longitudinal Study suggests that: 1) Joint degeneration due to osteoarthritis is a relatively slow process. The maximum rate of degeneration is seen in the distal interphalangeal joints where the average increase is about 1 grade per individual in an interval of 12 to 16 years between visits in each age group. The rate of degeneration in the proximal interphalangeal joints is much lower than that of the distal interphalangeal joints. 2) The progress of the degeneration in the distal interphalangeal joints of an individual (longitudinally evaluated) follows closely that which is observed at the population level (cross-sectional joint-digit study). That is, it is directly related to the age and the interval between visits. This is not always seen in the proximal interphalangeal joint data. 3) The rate of change in the osteoarthritic grade of individual hands agrees closely with that of their distal interphalangeal joints. This further supports the conclusions reached in a first report that what has been referred to as osteoarthritic grade of the hand of an individual may actually be the higher grade among the distal interphalangeal joints.