100 patients scheduled for total hip arthroplasty were randomized to receive either a cluster-hole acetabular cup or a solid-backed acetabular cup. All cases were completed with a crosslinked polyethylene line. The primary purpose of this study was to compare the rates of osteolysis development between the two types of acetabular cup. Follow-up was performed for 10 years. Results demonstrated that there was no significant difference in the rate of osteolysis development between patients who received the cluster hole acetabular cup and patients who received the solid-backed acetabular cup.