Boundary lubricating property of synovial fluid on artificial material and lubrication of artificial joints.

Boundary lubricating property of the synovial fluid on artificial materials was investigated by using a pendulum-type friction tester. The coefficient of friction between metal and metal with synovial fluid as a lubricant ranged from 0.19 to 0.30. Those between metal and plastic in the same condition ranged from 0.26 to 0.43. It is concluded from the above data that synovial fluid is a poor lubricant for artificial materials. The coefficient of friction of a metal on plastic prosthesis was approximately five times better than that of a metal on metal prosthesis in the pendulum experiments using synovial fluid as a lubricant.