Prostheses are fatigue tested using an apparatus under simulated physiological loading conditions. A fluid housing defines an entrance chamber having fluid outflow ports and an exit chamber having opposing fluid inflow ports and a central flow conduit in communication with the entrance chamber and the exit chamber. A plurality of housing tubes into which prosthesis are deployed may extend between the fluid outflow and inflow ports. Alternatively, tubular prostheses may be connected directly between the inflow and outflow ports. A reciprocating linear drive pump having a flexible diaphragm is provided to cyclically pressurize fluid through a common closed loop within the fluid housing and drive the pressurized fluid through the prosthesis being tested. The test system is capable of rotation independent of the motor drive for accurate diameter measurements of all test samples at elevated frequencies.