Granulocyte-macrophage colony stimulating factor in the aseptic loosening of total hip arthroplasty

Aseptic loosening of total hip arthroplasty (THA) seems to be associated with and perhaps caused by a synovial-like membrane developing at the implant-bone or cement-bone interface. Granulocyte-macrophage colony stimulating factor (GM-CSF) stimulates bone resorption directly and by recruiting and activating osteoclasas. It may link the synovial-like membrane and osteolysis of the surrounding bone. Twenty samples of synovial-like membrane from the implant-bone or cement-bone interface and from the pseudocapsule were obtained from ten patients undergoing hip revision surgery due to aseptic loosening of THA. As a control group, ten samples of non-inflammatory synovial membrane were obtained from knee joints. All samples were stained immunohistochemically, Results were quantitated by a semiautomatic image analysis system. GM-CSF positive cells, mostly macrophages, were found in all periprosthetic tissues. The number of GM-CSF positive cells per mm(2) was higher in synovial-like membrane and pseudocapsule around loose THAs than in the controls (p < 0.01). The results of the present study suggest that GM-CSF is expressed and produced by periprosthetic tissue cells. It may well cause periprosthetic bone loss and aseptic loosening of THA, and deserves more detailed studies as a mediator and potential target in the prevention of loosening.