The preoperative and early postoperative radiographs of 50 patients undergoing femoral impaction grafting with a modified Charnley stem and dedicated impaction grafting instrumentation were assessed to determine the predictability of the cement mantle being produced. The minimal cement mantle thickness was >2 mm in 76.7%, <2 mm in 12.7%, and absent in 10.7% of Gruen zones analyzed. There was no obvious zonal distribution to the areas of adequate or inadequate cement thickness. These values compare favorably with the results of other systems, and this may be due, in part, to a greater differential between the size of the graft impactors and the definitive prostheses.