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.

This is a three-group randomized placebo-controlled double blind trial to assess which postoperative analgesia is best after total hip replacement. The conventional analgesia includes both intrathecal morphine at surgery and Patient Controlled Analgesia (PCA) with morphine in the first 48 hours after surgery. This will be compared with two experimental groups which will receive either intrathecal morphine and PCA with placebo or intrathecal placebo and PCA with morphine. Escape medication with intramuscular morphine is available in all groups. A total of 120 patients will be randomized.

VAS- score at rest and with movement will be recorded every three hours for the first 48 hours after surgery, as well as PCA-bolussum and Morphine IM.

Inclusion Criteria:

• Patients accepted for fast-track total hip replacement, i.e.ASA 3 or lower

Exclusion Criteria:

• Not able to speak dutch
• communication problems
• dementia
• mental retardation