Lymphadenopathy caused by abraded metal debris drained from sites of joint prostheses.

The use of metal prostheses to replace large joints has become a common practice during the past decade. As a consequence, cases have been reported of the presence of metal-wear debris in local and distant lymph nodes (1,2,3,4,5,6,7,8,9,10,11) and in bone marrow, liver, and spleen (9,12). Stainless steel, cobalt, chromium, titanium, zirconium, nickel, barium, and ceramic are used to construct hip and knee prostheses; cementing materials, particularly polyethylene, are also used. Most modern joint prostheses are made of stainless steel or cobalt–chrome alloy (2). Polyethylene or ceramic is used to fashion the articulating surface, and polymethylacrylate to cement the prosthesis in place (1,5,8,9). The amount of metal carried to distant organs is highest in patients with loose and worn prostheses, and the superficial coating is the main source of debris (2). However, levels of metal may also be raised in patients whose prostheses show no visible wear (2,11), and, to a lesser extent, in those who have hip screws; such increases indicate the potential for widespread dissemination of foreign materials (2). The largest number of particles carried to the regional lymph nodes are of polyethylene, which is easily abraded and causes most of the reactive histiocytic proliferation. Titanium dioxide, deposited as black pigment in the cells, may cause intense damage in the form of necrosis and fibrosis in the lungs and lymph nodes of workers inhaling titanium in paint factories (12). In the joints, the accumulations of macrophages and T lymphocytes lead to aseptic osteolysis (9) and loosening of prosthesis, whereas in the lymph nodes the expression of a variety of cytokines, including tumor necrosis factor-α and interleukins 1B and 6 can be demonstrated (7).