To describe changes in muscle strength in the hands of children with juvenile chronic arthritis (JCA) and to examine the relationship between muscle strength, presence of local arthritis and disease subtype.
Twenty children (10 girls and 10 boys) with JCA aged 7 to 18 y were followed for two years. Isometric muscle strength in wrist dorsiflexors and handgrip strength were measured repeatedly. The results were compared with reference values for the same methods. Arthritis severity in the hand was scored every third month. Nerve conduction velocities were measured twice.
Seven out of 20 patients had initially low or decreasing strength in one or both of the two tests. Five out of 20 children had reduced strength (more than two standard deviations below the mean of the reference group) in at least one test. Four children showed a significant reduction in muscle strength in at least one test during the observation time. The greatest reduction in strength was measured in four children with polyarticular disease. These children also had local arthritis in the hand. A greater proportion of children with polyarthritis had low or decreasing strength compared with children with oligoarthritis. The same was true for children with active arthritis in the hand. Nerve conduction velocities were normal in all cases and did not change.
The majority of children with JCA have normal strength in the hand. Some children, especially those with polyarthritis and hand arthritis, have reduced muscle strength in the hand. Risk factors for low or decreasing strength are polyarthritis and/or active arthritis in the hand.