[Imaging in Kienböck's Disease]

In recent years, our increased knowledge about the biomechanics of the wrist and reparative mechanisms in osteonecrotic bones has significantly influenced the imaging procedures in Kienböck's disease as well as its differential diagnosis. In addition to projection radiography, computed tomography (CT) is used for evaluating the osseous microstructure, and contrast-enhanced magnetic resonance imaging (MRI) for determining the viability of bone marrow. CT is essential in the morphological staging of Kienböck's disease due to its high sensitivity in detecting proximally located fractures (stage IIIa) and in visualising osteoarthritic lesions (stage IV). Bone marrow oedema of the lunate bone as well as the zonal layers including the proximal necrotic zone, the middle reparative zone, and the distal viability zone can be depicted only with the use of MRI. Furthermore, intravenous application of gadolinium is mandatory in MRI, because vascular differentiation of the osteonecrotic zone from the reparative zone is reliable only in MRI perfusion studies. By evaluating clinical, biomechanical and imaging findings synoptically, a differentiation of Kienböck's disease from ulnocarpal impaction syndromes, intraosseous ganglion cysts, the fibrocartilageous type of lunotriquetral coalition, and post-traumatic and inflammatory lesions is possible in over 80% of all cases.