Efficacy of Post Total Knee Arthroplasty Pain Control by Adductor Canal Block plus Morphine Around the Clock versus Adductor Canal Block plus Patient Control Analgesia Intravenous Morphine: a Randomized Controlled Trial

Abstract

Background: Total knee arthroplasty (TKA) can produce moderate to severe postoperative pain. Adductor canal block (ADB) combine with patient control analgesia (PCA) has been accepted in many hospitals. However, the number of PCA machines are limited in many hospitals. Objective: To compare the efficacy of postoperative TKA pain control using ADB plus morphine around the clock versus ADB plus intravenous morphine by PCA. Methods: Prospective randomized control trial study, the participants undergoing TKA, the study group were assigned to the ADB plus morphine around the clock (n=30) and the control group were ADB plus PCA (n=30). Postoperative pain was assessed with verbal numerical rating scale (VNRS) every 6 hours in the first 24 hours. The side effect, dosage of morphine consumption and the patient satisfaction were also recorded. The data were analyzed using descriptive statistic, unpaired t test or Wilcoxon range sum test for the comparison of postoperative VNRS and other continuous variables. The Pearson chi square or Fisher exact test were used for the comparison of discrete variables. Results: Demographic variables were similar in both groups. There were no significant differences in postoperative VNRS scores, both at rest and on motion, at 6, 12, 18 and 24 hours between ADB plus morphine around the clock and ADB plus PCA groups. The first 24 hours morphine consumption in the ADB plus PCA was significantly higher than in the ADB plus morphine around the clock group (P=0.031). The side effects and patient satisfaction were not significantly different between the two groups. Conclusion: The efficacy of post TKA pain control from ADB plus morphine around the clock is comparable with ADB plus intravenous morphine by PCA. Therefore, it can be used in the resource limited hospital.