The use of epidural morphine in patients undergoing total knee arthroplasty

Abstract

Sixty-six patients undergoing total knee arthroplasty were offered epidural morphine as a method of postoperative analgesia. Of the 66 patients, 50 completed the minimum protocol of 3 days in a special epidural monitoring unit and were thus available for study. In this study group, 86% stated that they obtained 75–100% relief of pain with each epidural injection. Greater than 90% of the patients rated the overall experience with epidural analgesia as excellent or good. Ninety percent stated that they would choose epidural morphine analgesia again if given the choice. Nausea and vomiting were the most common adverse effects, occurring in 34%. One patient experienced respiratory depression, which was reversed with Narcan. The most frequent complaint related to the procedure itself was the use of an apnea monitor; 18% of the patients considered this monitoring device intolerable. The progress of total knee arthroplasties in the epidural unit was monitored by range of motion achieved. At 72 hours the averge motion was 10°–87° and at the end of the hospital stay was 6°–98°. The total hospital bill for epidural morphine analgesic patients was $469 more than for a conventional arthroplasty patient, though the mean duration of hospital stay was 1.7 days less for the epidural morphine patients. Epidural morphine provided excellent but inconsistent postoperative pain relief. When relief was present, aggressive in-house rehabilitation could be instituted, and a shorter overall hospital stay was achieved when compared with conventional analgesia. Nonetheless, the related adverse effects and inconsistent pain relief on many patients may preclude the use of epidural morphine as a single postoperative analgesic agent. © 1989, Churchill Livingstone Inc.. All rights reserved.