KIENBÖCK'S DISEASE, AVASCULAR NECROSIS OF THE LUNATE

Introduction: Avascular necrosis of the lunate bone was described in 1910 by the Austrian radiologist Robert Kienböck, which is named after him. A mixture of different factors such as mechanical, vascular and genetic predisposition may be related to the pathogenesis of this disease. As for the natural evolution of the disease, failure in early diagnosis and early treatment may lead to a gradual evolution from stage I to stage IV, causing discomfort to the patient. Objective: to detail the current information related to avascular necrosis of the lunate, description, etiology, classification, imaging presentation and management of Kienböck's disease. Methodology: a total of 32 articles were analyzed in this review, including review and original articles, as well as clinical cases, 20 bibliographies were used because the other articles were not relevant for this study. The sources of information were PubMed, Google Scholar and Cochrane; the terms used to search for information in Spanish, Portuguese and English were: Kienböck, avascular necrosis of the lunate and lunatomalacia. Results: it is the second most frequent cause of avascular necrosis of the carpal bones and generally affects males between 20 and 40 years of age. Nuclear magnetic resonance has a greater contribution due to greater sensitivity and detection of radiographically occult cases, computed tomography also has a good specificity at the time of diagnosis. Radiography at the beginning of the disease does not present evident changes and nuclear scintigraphy presents non-specific findings. In the first stage, the treatment is based on immobilization with a plaster cast or splints. When incomplete necrosis is evidenced in the second stage, conservative treatment can be performed, however with complete necrosis or in the third and fourth stage, it requires "joint leveling" surgery and probably vascular bone grafting or transfer of branches of adjacent arteries. Stage IIIA usually merits lunate restoration, in stage IIIB and Lichtman IV wrist arthrodesis can be used. Conclusions: Kienböck's disease presents with unilateral pain over the dorsal aspect of the wrist, weakness and limited wrist motion, in addition to functional impotence, decreased grip strength, wrist edema, sensory disturbances in the median nerve territory and synovitis, depending on the stage. It is related to the following variables such as ulnar minus or ulnar negative variation, vascular contribution of the lunate bone, morphology of the lunate, radial inclination angle. The diagnosis is clinical and imaging where Lichtman's classification is useful. Treatment will depend on the cause and also on the stage of the disease.