INDIRECT TRAUMA TO THE GROWTH PLATE - RESULTS OF MR IMAGING AFTER EPIPHYSEAL AND METAPHYSEAL INJURY IN RABBITS

Abnormalities of the growth plate secondary to epiphyseal and metaphyseal injury were studied with magnetic resonance (MR) imaging, radiography, and histologic examination in 20 rabbits. Epiphyseal injury resulted in either the formation of a bony bridge across the growth plate or focal curving of the growth plate caused by a decrease in longitudinal growth. Metaphyseal injury resulted in interference with endochondral ossification, thickening of the growth plate, and extension of cartilage into the metaphysis. Serial MR images obtained during the first 6 weeks after injury showed persistence of abnormalities of the growth cartilage after epiphyseal injury, but resolution of abnormalities after metaphyseal injury. Abnormalities of the cartilage were best seen on T2-weighted images. Gadolinium enhancement showed reconstitution of metaphyseal vascularity after metaphyseal injury but did not enable detection of transphyseal vascularity after epiphyseal injury until a bony bridge formed.