Intrathecal morphine verse femoral nerve block for pain control in total knee arthroplasty: A meta-analysis from randomized control trials.

OBJECTIVE: Total knee arthroplasty (TKA) is usually associated with postoperative pain. The objective of this systematic review and meta-analysis was to evaluate the effectiveness and safety of femoral nerve block compared with intrathecal morphine for pain management after TKA.

METHODS: Potentially relevant literature was identified from electronic databases including Medline, PubMed, Embase, ScienceDirect and the Cochrane Library. Gray academic studies were also identified from the reference of included literature. There was no language restriction. Pooling of data was carried out using Stata 11.0.

RESULTS: Four randomized controlled trials (RCTs) involving 185 patients met the inclusion criteria. The meta-analysis indicated that there were no significant differences in terms of Visual Analog Scale (VAS) score at 6 h (standard mean difference (SMD) = -0.09, 95% CI: -1.62 to 1.43, P = 0.903), 12 h (weighted mean difference (WMD) = 1.84, 95% CI: -8.01 to 11.69, P = 0.714) or 24 h (WMD = 1.56, 95% CI: -14.31 to 17.42, P = 0.8474). No significant difference were found regarding morphine consumption at 6 h (WMD = -0.84, 95% CI: -2.52 to 0.85, P = 0.332), 12 h (WMD = 0.031, 95% CI: -3.304 to 0.3366, P = 0.985), 24 h (WMD = 0.21, 95% CI: -7.32 to 7.75, P = 0.956) or incidence of postoperative vomit and nausea (risk difference (RD) = -0.01, 95% CI: -0.15 to 0.12, P = 0.847). There was a significant difference between the groups in terms of the risk of itching postoperatively (RD = 0.41, 95% CI: 0.29 to 0.54, P < 0.001).

CONCLUSIONS: Femoral nerve block provides equal postoperative pain control compared with intrathecal morphine following total knee arthroplasty, although there were fewer side effects in the FNB groups. In contrast, FNB was performed with an additional procedure and required a special apparatus. Both methods are effective at pain control following TKA.