The use of gabapentin in the management of postoperative pain after total knee arthroplasty A PRISMA-compliant meta-analysis of randomized controlled trials

Pain management after total knee arthroplasty (TKA) varies and has been widely studied in recent years. Some randomized controlled studies have carried out to evaluate the effects of gabapentin on pain relief after TKA. However, no solid result was made about it. The purpose of this Meta-Analysis of Randomized Controlled Trials (RCTs) was to estimate the overall effect of pain control of gabapentin versus placebo after a TKA. An electronic-based search using the following databases: PubMed, EMBASE, Ovid MEDLINE, ClinicalTrials.gov, and Cochrane Central Register of Controlled Trial from 1966 to June 2015. RCTs involving gabapentin and placebo for total knee arthroplasty were included. The meta-analysis was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Six trials with 859 participants met the inclusion criteria. The primary endpoint was cumulative narcotic consumption and the visual analog scale scores at 12 hours, 24 hours, and 48 hours, postoperatively. The knee flexion degree and treatment side effects were also compiled to evaluate the safety of gabapentin. After testing for the heterogeneity and publication bias among studies, data were aggregated for random-effects modeling when necessary. There was a significant decrease in morphine consumption at 12 hours (MD = -4.69, 95% CI: -7.18 to -2.21, P = 0.0002), 24hours (MD = -5.30, 95% CI: -9.94 to -0.66, P = 0.03), and 48 hours (MD=-17.80, 95% CI: -31.95 to -3.64, P = 0.01), respectively. Compared with the control group, the rate of pruritus was less in the gabapentin group (RR 0.20, 95% CI 0.10 to 0.38, P = 0.00). In summary, the administration of gabapentin was effective in decreasing postoperative narcotic consumption and the incidence of pruritus. There was a high risk of selection bias and a higher heterogeneity of knee flexion range in this analysis. More high-quality large randomized controlled trials with long follow-up period are necessary for proper comparisons of the efficacy and safety of gabapentin with placebo. Systematic review registration number: No.