Kienbock's disease.

Kienböck's disease is a form of osteonecrosis affecting the lunate. Its aetiology remains unknown. Morphological variations, such as negative ulnar variance, high uncovering of the lunate, abnormal radial inclination and/or a trapezoidal shape of the lunate and the particular pattern of its vascularity may be predisposing factors. A history of trauma is common. The diagnosis is made on plain radiographs, but MRI can be helpful early in the disease. A CT scan is useful to demonstrate fracture or fragmentation of the lunate. Lichtman classified Kienböck disease into five stages. The natural history of the condition is not well known, and the symptoms do not correlate well with the changes in shape of the lunate and the degree of carpal collapse. There is no strong evidence to support any particular form of treatment. Many patients are improved by temporary immobilisation of the wrist, which does not stop the progression of carpal collapse. Radial shortening may be the treatment of choice in young symptomatic patients presenting with stages I to III-A of Kienböck's disease and negative ulnar variance. Many other forms of surgical treatment have been described.