The ideal thickness of cement between the prosthesis and bone has not been accurately determined, but there is general agreement that the surgeon should be able to provide and accurately produce a certain thickness of cement between the prosthesis and the bone. Conventional cementing technique could allow the surgeon to ovepush the cup into direct contact with the bone producing a very thin cement coat or a void. We have developed a simple method of achieving a predictable thickness. We insert small spacers made of methylmethacrylate, which can be placed between the bone of the acetabulum and the acetabular component, preventing voids or thin areas in the cement coat. The device has been used in over 50 patients and has proven to be a simple and reliable method of allowing the surgeon to produce a predictable thickness of cement surrounding a joint replacement component. An additional benefit obtained from the use of these spacers is the ability to rigidly hold the acetabular component during polymerization of the acrylic without fear of overpushing. This allows better packing of the bone cement and prevents imperfections caused by the cup contacting the bone.