DEVELOPMENT OF A NEW ARTIFICIAL LUBRICANT WITH A CONSTANT COMPOSITION FOR WEAR CHARACTERIZATION OF ARTIFICIAL HIP JOINTS AS A SUBSTITUTE FOR BOVINE SERUM

摘要

In accordance with international standard, wear tests of artificial hip joints have been generally performed in a bovine serum solution, whose composition is not the same as that of human joint fluid. It is known that its composition easily varies by manufacturing processes. The difference in composition has, however, large effect on the wear characterization. It was not always easy to get reproducible results because of their variability in concentration. Therefore, it is desirable to develop an artificial lubricant whose composition can be always set to a specified value as an alternative to bovine serum. In the present study, several lubricants composed of one or plural major components in bovine serum such as albumin, γ-globulin and phospholipid with some additives were prepared as an alternative to bovine serum. The effect of them on wear characteristics was studied by hip simulator. As a result, the transparent and stable lubricants with specified concentrations of components were successfully prepared. As for protein, the wear rate in globulin solution was larger than that in albumin. As for phospholipid, it could reduce the wear rates, when it coexists with protein. The solution with albumin and γ-globulin showed slightly similar wear rates to the bovine serum. These results serve as a guide to propose a new lubricant fluid suitable for the wear characterization of artificial hip joints.