62 patients scheduled for total hip arthroplasty were randomized to either a monoblock, vitamin E infused highly-crosslinked polyethylene cup (HXLPE/VitE) or a monoblock, ultra-high-molecular-weight polyethylene cup. Patients were assessed for three-dimensional femoral head penetration, using radiostereometric analysis, and clinical scores over 3-year follow-up. Groups demonstrate a non-significant difference in femoral head creep during the first 6 months after surgery; thereafter, femoral head penetration was significantly lower in the HXLPE/VitE group compared to UHMWPE group at all time points to 3 years. No significant differences between groups in clinical scores after 3 years were observed.