A Single-Dose Intra-Articular Morphine plus Bupivacaine versus Morphine Alone following Knee Arthroscopy: A Systematic Review and Meta-Analysis

Abstract

Objectives: The purpose of this study was to compare the efficacy and safety of a single-dose intra-articular morphine plus bupivacaine versus morphine alone in patients undergoing arthroscopic knee surgery.

Methods: Randomized controlled trials comparing a combination of morphine and bupivacaine with morphine alone injected intra-articularly in the management of pain after knee arthrocopic surgery were retrieved (up to August 10, 2014) from MEDLINE, the Cochrane Library and Embase databases. The weighted mean difference (WMD), relative risk (RR) and their corresponding 95% confidence intervals (CIs) were calculated using RevMan statistical software.

Results: Thirteen randomized controlled trials were included. Statistically significant differences were observed with regard to the VAS values during the immediate period (0-2h) (WMD -1.16; 95% CI -2.01 to -0.31; p = 0.007) and the time to first request for rescue analgesia (WMD = 2.05; 95% CI 0.19 to 3.92; p = 0.03). However, there was no significant difference in the VAS pain score during the early period (2-6h) (WMD -0.36; 95% CI -1.13 to 0.41; p = 0.35), the late period (6-48h) (WMD 0.11; 95% CI -0.40 to 0.63; p = 0.67), and the number of patients requiring supplementary analgesia (RR = 0.78; 95% CI 0.57 to 1.05; p = 0.10). In addition, systematic review showed that intra-articular morphine plus bupivacaine would not increase the incidence of adverse effects compared with morphine alone.

Conclusion: The present study suggested that the administration of single-dose intra-articular morphine plus bupivacaine provided better pain relief during the immediate period (0-2h), and lengthened the time interval before the first request for analgesic rescue without increasing the short-term side effects when compared with morphine alone.

Level of evidence: Level I, meta-analysis of Level I studies.

Fig 1. Flow chart of the selection of articles.

Fig 2. Forest plot of meta-analysis: visual analogue scale score of postoperative pain intensity in the immediate period (0-2h).

M, morphine; B, bupivacaine; SD, standard deviation; IV, inverse variance; CI, confidence interval.

Fig 3. Funnel plot of meta-analysis: visual analogue scale score of postoperative pain intensity in the immediate period (0-2h).

WMD, weighted mean difference.

Fig 4. Forest plot of meta-analysis: visual analogue scale score of postoperative pain intensity in the early period (2-6h).

M, morphine; B, bupivacaine; SD, standard deviation; IV, inverse variance; CI, confidence interval.

Fig 5. Funnel plot of meta-analysis: visual analogue scale score of postoperative pain intensity in the early period (2-6h).

WMD, weighted mean difference.

Fig 6. Forest plot of meta-analysis: visual analogue scale score of postoperative pain intensity in the late period (6-48h).

M, morphine; B, bupivacaine; SD, standard deviation; IV, inverse variance; CI, confidence interval.

Fig 7. Funnel plot of meta-analysis: visual analogue scale score of postoperative pain intensity in the late period (6-48h).

WMD, weighted mean difference.

Fig 8. Forest plot of meta-analysis: time to first analgesic request.

M, morphine; B, bupivacaine; SD, standard deviation; IV, inverse variance; CI, confidence interval.

Fig 9. Funnel plot of meta-analysis: time to first analgesic request.

WMD, weighted mean difference.

Fig 10. Forest plot of meta-analysis: number of patients requiring supplementary analgesia.

M, morphine; B, bupivacaine; SD, standard deviation; IV, inverse variance; CI, confidence interval.

Fig 11. Funnel plot of meta-analysis: number of patients requiring supplementary analgesia.

WMD, weighted mean difference.