Abstract: A cement retaining shield for use when seating an acetabular prosthetic implant into a cement filled acetabulum. The shield includes at least two leaf-like sections which may be displaced outwardly by rotation of a cam to cover a substantial portion of the patient's acetabulum. The device is particularly useful in applying force through the shield to compress the cement into the acetabulum to improve bonding at the cement-bone interface and at the cement-implant interface. Preferably, the shield is in the form of a planar disc and the leaf-like sections are positioned in overlying relationship to the disc. The sections, responsive to the rotation of a cam, may be extended outwardly of the disc.