Low Dose Extended-release Epidural and Lumbar Plexus Block Compared to Lumbar Plexus Block for Total Hip Resurfacing

Extended release epidural morphine (EREM, DepoDur®: Endo Pharmaceuticals, Chadds Ford PA) has
been studied and increasingly utilized as a method to allow for the improved post-operative
analgesia of epidural analgesia without infusions.

At Wake Forest University, the investigators have been using EREM, since late 2004, as part
of multimodal analgesia in patients having gynecologic surgeries and hip arthroplasties. The
investigators initially decreased our dosages from those recommended (15 mg for lower
extremity surgery and 10-15 mg for abdominal surgery), because side effects (nausea, vomiting
and hypotension) were felt to be limiting to recovery. The investigators now use 4-7.5 mg in
most patients, with 7.5 mg being the exception and have achieved better results. For hip
arthroplasties, the investigators currently use 4-5 mg and have performed two retrospective
chart reviews on this use; both suggesting that this approach is efficacious. However, these
doses have not been studied in a prospective, randomized, double blind trial. The
investigators would like to evaluate the efficacy of this dose of EREM used as part of a
multimodal regimen. The investigators will compare EREM 4 mg with lumbar plexus block versus
lumbar plexus block alone, (providing the rest of our multimodal approach for both patients).

Inclusion Criteria:

- A primary unilateral Birmingham hip arthroplasty

- Men and women 18-65 years

Exclusion Criteria:

- Refusal of regional anesthesia

- Laboratory evidence of coagulopathy (platelet count less than 100,000 cells/microliter
of blood, prothrombin time greater than 12.1 seconds, partial thromboplastin time
greater than 30 seconds, or international normalized ratio of greater than 1.5)

- Allergy to morphine

- Obstructive sleep apnea

- Body mass index (BMI) greater than 40 kg/m2

- Pregnant or lactating

- Severe renal or hepatic disease