In patients with hypoplasia of the ulna, the role of the
fibrocartilaginous anlage of the ulna in the development of deformity is
controversial. Between 1971 and 1982, we treated eight such patients with
eleven affected extremities. We maintained them on a conservative regimen
of static splinting, and surgery was not undertaken unless there was
uncorrectable ulnar deviation at the wrist of 30 degrees or more. Resection
of the anlage had to be performed in only one patient. Progression of
uncorrectable ulnar deviation at the wrist rarely occurs in patients with
ulnar deficiency; therefore, routine precautionary excision of the anlage
is not justified.