Low-dose intrathecal morphine for total knee arthroplasty

Abstract

A review of 141 patients undergoing total knee arthroplasty included 86 patients receiving low-dose intrathecal morphine with spinal anaesthesia (Group A) and 55 patients receiving general inhalation anaesthesia (Group B). The mean dose of intrathecal morphine sulphate was 0.26 mg. Patients in Group A averaged 1.1 post-operative days to first ambulation and 2.9 days to unassisted ambulation. Group B patients were first ambulant in 2.45 days and independently ambulant in 5.6 days. The mean stay for Group A patients was 4.9 days and for Group B patients 7.8 days. Group A patients averaged 83° of flexion on the first post-operative day compared with 38° of flexion in Group B. In Group A, 8% of patients received meperidine averaging 240.7 mg, 37% received morphine sulphate averaging 10.7 mg, 5% received a combination of parenteral narcotics and 50% received no parenteral analgesics. In Group B, 65% received meperidine averaging 290.2 mg, 23% received morphine sulphate averaging 68.5 mg and 5% received no parenteral analgesics. There were no cases of respiratory depression and the incidence of nausea was not significantly different in the two groups. However, more pruritis was noted in Group A.