Lessons Learned with Extended-release Epidural Morphine after Total Hip Arthroplasty

An extended-release epidural morphine (EREM) has been introduced to improve postoperative pain management. Studies have shown the effectiveness of this agent in providing better pain control and patient satisfaction for patients undergoing total joint arthroplasty. We evaluated postoperative pain relief by comparing average daily pain scores and opioid use with those of the control group. Safety was measured by comparing the occurrence of postoperative complications, nausea and vomiting, pruritus, and respiratory depression between the two groups. Between February 2006 and March 2008, we selected 203 patients to receive EREM for THA. These patients were matched in a 2:1 ratio with patients undergoing THA and receiving spinal anesthesia. We retrospectively reviewed all major and minor postoperative complications from a prospective database. Patients receiving EREM had lower pain scores than patients not receiving EREM on Postoperative Day 1 (POD 1) but not POD 2, or POD 3. Patients receiving EREM experienced a slightly higher incidence of pulmonary embolism and supraventricular tachycardia. Patients receiving EREM also experienced more nausea and vomiting and pruritus. We found EREM provided better pain relief on POD 1 at the expense of a slightly higher incidence of side effects compared with spinal anesthesia alone.