We evaluated 59 hips that underwent a primary total hip arthroplasty using an S-ROM modular femoral component at a mean follow-up of 101 months (range, 72-145 months). All cases showed radiographic evidence of bone ingrowth, and there were no femoral revisions for aseptic loosening. The Harris hip score improved from a mean of 40 preoperatively to 89 at final follow-up. Some degree of proximal femoral disuse atrophy from stress shielding occurred in 46 hips (78%), and some degree of femoral osteolysis occurred in 25 hips (42%). Only additional follow-up will reveal whether there is a consequence of both types of proximal femoral bone loss.