114 patients undergoing primary elective total hip replacement (THR) under spinal anaesthesia were randomized to determine the comparative efficacy of oral oxycodone with i.v patient-controlled analgesia (IVPCA) as a method of postoperative analgesia. Patients received either Oxycontin 20mg or IVPCA with morphine, and were monitored for pain and nausea in the first 72 hours postoperatively. The results demonstrated that oral oxycodone was non-inferior to IVPCA with morphine, as pain and nausea scores were observed to not significantly differ between groups.