IMAGING AND STAGING OF AVASCULAR OSTEONECROSES AT THE WRIST AND HAND

Avascular ostenecroses (AVN) are unspecific focal sceletal lesions of vascular origin. At the wrist, AVNs are mainly seen in the lunate (Kie nbock's disease) and the proximal scaphoid fragment in the presence of a nonunion disease (pseudarthrosis). Other types of osteonecroses are rare. The natural process of devitalization proceeds in steps: initia lly, there is a bone marrow oedema, followed by trabecula sclerosis, c ystic transformation of the spongiosa, and bone fragmentation. End sta ges include carpal collapse (SLAG wrist) and osteoarthritis. For imagi ng of the sceletal morphology in AVN computed tomography is most usefu l, whereas initial stages and perfusion damages are better detected wi th contrast enhanced magnetic resonance imaging (MRI). In this paper a staging classification for Kienbock's disease and the scaphoid nonuni on, considering the diagnostic and therapeutic consequences, is presen ted. (C) 1997 Elsevier Science Ireland Ltd.