Analgesic Effect of Pre-Emptive Gabapentin on Knee Surgery: A Systematic Review and Meta-Analysis

We aimed to evaluate the effectiveness of preemptive oral gabapentin on postoperative analgesia after knee surgery. Gabapentin is widely known to reduce postoperative pain scores and opioid requirements following a variety of surgeries. We searched MEDLINE (January 1, 1976 to April 30, 2014), EMBASE (January 1, 1985 to April 30, 2014), the Cochrane Library (January 1, 1987 to April 30, 2014), and KoreaMed (June 1, 1958 to April 30, 2014). A total of 225 patients in 4 studies were included in the study. The overall pooled results from meta-analysis demonstrated that compared with placebo, pre-emptive analgesia could significantly reduce the postoperative pain score [mean difference (MD) −6.29; 95% confidence interval (CI) −10.17 to −2.42; P = 0.001; random-effect model]. The subgroup analyses found that gabapentin significantly reduced the postoperative pain score in patients who underwent general anesthesia (MD, −17.82; 95% CI, −21.82 to −13.81; P = 0.47; fixed-effect model). The subgroup analyses could not clarify the effectiveness of gabapentin on reducing postoperative pain in patients who underwent regional anesthesia (MD, 2.43; 95% CI, −1.14 to 6.00; P = 0.78; fixed-effect model). Pre-emptive gabapentin reduced early postoperative pain scores. However, it was unclear whether gabapentin reduces postoperative pain score in the setting of regional anesthesia or multimodal analgesic regimen.