Published online Nov 27, 2016. doi: 10.5313/wja.v5.i3.67
Peer-review started: May 12, 2016
First decision: July 11, 2016
Revised: July 27, 2016
Accepted: September 13, 2016
Article in press: September 18, 2016
Published online: November 27, 2016
To compare the efficacy of intrathecal morphine and single shot femoral nerve block for patients undergoing primary total knee arthroplasty.
Data was extracted from electronic medical records and case-paper record files of patients who underwent unilateral primary total knee arthroplasty under spinal anesthesia using bupivacaine 12.5 mg with intrathecal morphine (ITM) 0.2 mg and under general anesthesia (GA) with single shot femoral nerve block (FNB) using 20 mL 0.5% bupivacaine at our hospital in 2013 and 2014. All patients had received peri-articular infiltration as per the hospital protocol. Data for gender, age, weight, American Society of Anesthesiologists status, total surgical time, postoperative pain score using visual analogue scale (VAS) from 1 to 10 at 6 h, 12 h and 24 h postoperatively, 24 h opioid consumption, use of oral multimodal analgesia, postoperative high dependency unit (HDU) admission and the time to discharge from the hospital was collected. The data was analyzed using Mann-Whitney U test for continuous variables and Fischer’s exact-t-test for categorical variables.
Twenty-two patients in ITM group and 32 patients in FNB group were analyzed. Median pain scores using VAS in ITM group were significantly lower at 6 h (0.0 vs 2.0, P < 0.001), 12 h (0.0 vs 2.0, P < 0.001) and 24 h (0.0 vs 2.0, P < 0.001) postoperatively. Also, postoperative morphine consumption in ITM group was significantly lower (P < 0.001). However, median of non-steroid anti-inflammatory drug unit requirement in 24 h postoperatively was statistically significant higher in ITM compared to FNB group (2.0 vs 1.0, P = 0.025). The difference in postoperative paracetamol consumption in 24 h was not statistically significant (P = 0.147). There was no significant difference in the postoperative HDU admission or time to discharge from the hospital. No respiratory depression in either group was noticed.
The ITM group patients had much lower pain scores and morphine requirement in the first 24 hour postoperatively compared to FNB group.
Core tip: In this retrospective analysis, intrathecal morphine (ITM) with spinal anesthesia and single shot femoral nerve block (FNB) with general anesthesia were compared in 54 patients undergoing primary total knee arthroplasty over two years at our institute. Pain scores and morphine consumption in 1st 24 h after surgery were significantly lower in ITM group compared to FNB group (P < 0.001); while complication rates, high dependency unit admission rates, and time to discharge from the hospital were similar in both groups. Also, patients in ITM group were highly satisfied (P < 0.001).