Treatment of postoperative pain should rely on results from randomized controlled trials and meta-analyses of high scientific quality. The efficacy of a particular intervention may depend on the type of surgical procedure, which supports the reporting of "procedure-specific" interventions. The aim of this systematic review was to document the procedure-specific evidence for analgesic interventions after total hip arthroplasty (THA). This PRISMA-compliant and PROSPERO-registered review includes randomized placebo-controlled trials (RCTs) of medication-based analgesic interventions after THA. Endpoints were postoperative opioid consumption, pain scores (rest and during mobilization), adverse events, and length of hospital stay. Fifty-eight trials with 19 different interventions were retrieved. High risk of bias, substantial differences in assessment-tools and criteria for pain, irregular reporting of adverse events, considerable differences in supplemental analgesic consumption, and basic analgesic regimens generally characterized trials. Meta-analyses of non-steroidal anti-inflammatory drugs, local infiltration analgesia, intrathecal opioids, and lumbar plexus block provided a 24-hour intravenous morphine-sparing effect of 14.1 (95 % confidence interval: 8.0-20.2) mg, 7.5 (3.7-11.3) mg, 19.8 (14.9-24.7) mg, and 11.9 (6.4-17.3) mg, respectively. Non-steroidal anti-inflammatory drugs and lumbar plexus block were demonstrated to provide reductions in postoperative pain scores. Intrathecal opioids increased pruritus, and lumbar plexus block reduced nausea and pruritus. The GRADE-rated quality of evidence ranged from low to very low throughout the analyses. This review demonstrated, that some analgesic interventions may have the capacity to reduce mean opioid requirements and/or mean pain intensity compared with controls, but the available randomized placebo-controlled trials does not allow a designation of a "best proven intervention" for THA.

Pregabalin has demonstrated anti-hyperalgesic properties and was introduced into acute pain treatment in 2001. Our aim was to evaluate the beneficial and harmful effects of pregabalin in postoperative pain management. We included randomized clinical trials investigating perioperative pregabalin treatment in adult surgical patients. The review followed Cochrane methodology, including Grading of Recommendations Assessment, Development, and Evaluation (GRADE), and used trial sequential analyses (TSAs). The primary outcomes were 24 h morphine i.v. consumption and the incidence of serious adverse events (SAEs) defined by International Conference of Harmonisation Good Clinical Practice guidelines. Conclusions were based primarily on trials with low risk of bias. Ninety-seven randomized clinical trials with 7201 patients were included. The 24 h morphine i.v. consumption was reported in 11 trials with overall low risk of bias, finding a reduction of 5.8 mg (3.2, 8.5; TSA adjusted confidence interval: 3.2, 8.5). Incidence of SAEs was reported in 21 trials, with 55 SAEs reported in 12 of these trials, and 22 SAEs reported in 10 trials with overall low risk of bias. In trials with overall low risk of bias, Peto's odds ratio was 2.9 (1.2, 6.8; TSA adjusted confidence interval: 0.1, 97.1). Based on trials with low risk of bias, pregabalin may have a minimal opioid-sparing effect, but the risk of SAEs seems increased. However, the GRADE-rated evaluations showed only moderate to very low quality of evidence. Consequently, a routine use of pregabalin for postoperative pain treatment cannot be recommended.

O. (2016). Gabapentin for postoperative pain management-a systematic review with meta-analyses and trial sequential analyses. This article included Trial Sequential Analyses (TSA) of the random-effects models used to adjust the confidence intervals (CI) for possible sparse data and repetitive testing. Unfortunately, due to a bug in the TSA program, the required information size (RIS) for continuous outcomes were calculated twice the correct value. There was no error in the calculations of RIS for dichotomous outcomes. However, even with an upgrade of the GRADE evaluation of the effect on the co-primary outcome of 24 hrs morphine consumption from 'very low' to 'low' the conclusions still hold and should not be changed. Accordingly, the authors present corrections for the following passages in the article: In the Abstract, Results section:

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