76 patients with primary osteoarthritis and secondary osteoarthritis due to mild dysplasia were randomized to receive either standard total hip arthroplasty (THA), large-head THA, or resurfacing hip arthroplasty (RHA) to examine the differences between these three treatments on long-term clinical function. Results at 2 years indicated that, although incision length and surgical time were significantly higher in the RHA group, there were no significant differences between groups in range of motion, Harris Hip scores (HHS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, UCLA activity scores, step rate or sick leave. There was no clinically relevant difference between groups in quality of life.