EXPERIMENTAL OSTEONECROSIS OF THE LUNATE - REVASCULARIZATION MAY CAUSE COLLAPSE

Is lunate collapse in Kienbock's disease a consequence of spontaneous revascularization, leading to focal osteolysis? A literature review of osteonecrosis in other locations such as the femoral head and bone al lografts showed clearly that the loss of mechanical integrity is due t o cellular processes which follow the spontaneous restoration of brood supply. We found no evidence in the literature that the lunate has be en shown to be avascular at the time of collapse. On the contrary, inc reased osteoclastic activity has been reported. We excised and reimpla nted the lunate in two monkeys, and found spontaneous revascularizatio n, leading to increased osteoblastic activity. Other parts of the bone were destroyed by osteoclasts, leading to collapse. This histological example suggests that it mag be possible to make an analogy with oste onecrosis in other locations. Thus, changes on plain radiography may i ndicate that the bone is revascularized spontaneously. Before performi ng operative revascularization of the lunate, one should consider that revascularization is a probable cause for collapse.