Congenital proximal radio-ulnar synostosis. Natural history and functional assessment.

We evaluated the cases of twenty-three patients with thirty-six congenital proximal radio-ulnar synostoses who had been followed between 1938 and 1984. None of the patients had had any attempt at surgical correction or any ipsilateral congenital anomalies. Emphasis was placed on analyzing the natural history of the lesion in these patients who had not been operated on, and on determining the effect of a fixed position of the forearm on function. Ten patients had unilateral and thirteen, bilateral synostosis. Their mean age when last examined was twenty-two years (range, three to fifty years). Eight patients were female and fifteen, male. The forearms were fixed in an average of 30 degrees of pronation. The position of the forearm was not found to be related to subjective functional limitations, employment status, or the results of the hand-function test of Jebsen et al. Most patients had few or no functional limitations, and were employed in jobs that demanded extensive use of the forearm. Contrary to the findings of other studies, we observed four distinct radiographic patterns based on the presence of an osseous synostosis and the position of the radial head. However, we noted no relationship between any of these patterns and function. We concluded that operative treatment of congenital radio-ulnar synostosis is rarely indicated, that less emphasis should be placed on the single factor of the position of the forearm, and that objective functional tests should be included in the assessment of these patients.