A hip simulator is used to measure joint friction under physiological loading conditions. The device is mounted on a standard uniaxial testing machine and allows the synchronised application of in-vivo joint forces with cyclic motion. The device is constructed to allow friction moment measurements to be decoupled from the applied load. Loading parameters are varied and water and serum are used as lubricant. Recently, implantation in foam blocks has allowed the influence of cup deformation on friction moments to be assessed.
N. E. Bishop, F. Waldow, and M. M. Morlock, Friction moments of large metal-on-metal hip joint bearings and other modern designs, Med.Eng Phys. 30 (8):1057-1064, 2008