抄録
Periprosthetic osteolysis can be radiologically classified into two types, linear osteolysis and cavitary osteolysis, which are combined in 15-25% of clinical cases of THA. Cavitary osteolysis is through to be due to a negative balance of osteoblast-osteoclast activity that is influenced by intercellular mediators released from activated macrophages to phagocytose wear-debris. In order to prevent such osteolysis, the amount of wear-debris must be significantly reduced by changing prosthesis design as well as bearing materials. In cemented THA, a prosthesis with a polished stem surface must be used to reduce the amount of cement debris. In cementless THA, HA coating and metal porous coating over the components must be replaced with alkali-heat treated Ti alloy to avoid 3rd body wear. For the bearing surface, ceramic-on-ceramic is preferred to metal-on-metal, as ion release might be a problem in the long term in the latter. Highly cross-linked PE-on-ceramic bearing would be another choice, although the best dose of irradiation on PE has not yet been determined and, therefore, the long-term results of this combination must be carefully observed.
