There are several treatments for postoperative pain after Hip Replacement Surgery. However, some require an intravenous line which may interfere with rehabilitation after surgery. This study aims to evaluate which method of pain treatment is best after Hip Replacement Surgery. Patients will either receive pain treatment at surgery, continuous intravenous pain treatment, or both. In the first two days after surgery, patients will frequently be asked to rate their pain, and use of other pain medication will be monitored.