Quantitative information regarding the interface strength and degree of cement penetration associated with cement viscosity during total hip arthroplasty is limited. The aim of the present study was to determine the effect of the viscosity of bone cement at the time of implantation on the mechanical integrity of total hip arthroplasty. Cement that was injected at an early less viscous stage produced greater failure strength in a push-out test than its more viscous counterpart.