Thirty-five patients who had multiple cartilaginous exostosis and
deformities of the wrist and forearm were evaluated to determine the
natural history and prognostic factors for the deformities. Radial and
ulnar shortening were correlated linearly (r2 = 0.86), showing that both
bones of the forearm were symmetrically involved. The angular growth
abnormality of the distal aspect of the radius was correlated with radial
shortening (r2 = 0.53) and ulnar shortening (r2 = 0.61), but it had no
correlation with negative variance of the ulnar (r2 = 0.30). Carpal slip
was an independent factor, with no correlation with any of the factors
studied. The ulnar tether theory for deformities of the wrist in patients
who have multiple cartilaginous exostosis was not substantiated by this
study.