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一项系统综述的结果显示，局部浸润镇痛（LIA）能为全膝关节置换术后早期提供有效的镇痛作用，而对全髋关节置换术后则疗效有限。

丹麦哥本哈根比斯柏格医院的Lasse O.Andersen博士称，局部浸润镇痛更适合于与以循证为基础的多模式全身性镇痛联用。对于全髋关节置换术，全身性镇痛已经足够（这点证据充分），使得局部浸润麻醉没有了额外的镇痛效果，但对于全膝关节置换术，局部浸润麻醉的镇痛效果总体而言是证据充分的，即使与多模式全身性镇痛联用。

研究人员注意到，先前的研究因为缺乏在接受了局部浸润镇痛的全身性镇痛与无接受局部浸润镇痛的全身性镇痛之间的比较而受到了限制。局部浸润镇痛技术的联用以及所用的药物也一直存在着多重方案。

Andersen博士和来自哥本哈根大学的Henrik Kehlet博士审慎地评估了对27例全髋关节置换术（THA）及全膝关节置换术（TKA）术中使用局部浸润镇痛的术后72小时的镇痛功效的随机试验进行的系统研究及综述。这项研究纳入了888位全膝关节置换术患者和756位全髋关节置换术患者。只有全髋关节置换术试验中的2例被认为存在低偏倚风险；剩余8例未双盲或者在全身性镇痛的控制组和干扰组中存在差异。在17例全膝关节置换术的试验中，只有2例被认为存在低偏倚风险。其余的都受到与全髋关节置换术试验相同的高偏倚风险。

据6月17日British Journal of Anaesthesia的报告，当联用多模式全身性镇痛疗法时，7例局部浸润镇痛的试验对比生理盐水或者无注射的全髋关节置换术的患者在疼痛评分上没有显著性差异。与之相反，7例类似的对全膝关节置换术患者的试验表现出接受了局部浸润镇痛的患者术后32小时疼痛评分的减少及阿片类药物的用量的减少。

由于在治疗组中不同的外周神经阻滞技术及不同的全身性镇痛的使用，对比局部浸润镇痛及外周神经阻滞（PNB）的试验是混淆的。

研究人员表示在对比局部浸润镇痛与硬膜外镇痛、全身性镇痛、硬模腔内吗啡镇痛试验的高偏倚风险限制了得出的关于有效性的最终结论的能力。类似的，在试验中表现出住院日的数据是多变的而且好像与镇痛技术的选择没有关系。

Andersen博士表示，“如果临床研究人员能提供类似的镇痛药给两组和所有的研究组，那么结论就会有意义-而文献报道的研究正是因为在局部麻醉剂/局部浸润镇痛方案采用了多种不同的镇痛药（非甾体类、类固醇、阿片类等等）而掺入了混杂因子。”

Andersen博士表示，“这就让人很难判定术中大量局麻药浸润是否比控制组的治疗方案提供更好的镇痛效果。”对于术后疼痛的研究，有必要尽量减小混淆因素，因为对术后疼痛的等级的的个体差异非常大，所以在设计将来的研究时需要引起对混淆因素的警觉。当评估局部浸润镇痛对住院时间（LOS）影响时，未来的研究应该分析“为什么这位患者今天住院”,因为综述明确表现了不充足的数据的情况以及总结得出局部浸润镇痛可能不影响住院时间，这取决于其他许多原因而不是疼痛。

Local InfiltrationAnalgesia Offers Pain Relief in Some Joint Surgeries

NEW YORK (ReutersHealth) - Local infiltration analgesia (LIA) provides effective analgesia earlyafter total knee arthroplasty but has limited efficacy after total hiparthroplasty, according to results of a systematic review.

LIA shouldpreferably be used in combination with evidence-based multimodal systemicanalgesia, Dr. Lasse O. Andersen from Bispebjerg Hospital in Copenhagen,Denmark told Reuters Health by email. For hip arthroplasty, systemicanalgesia will be adequate (this is well-documented) with no additionalanalgesic effect of LIA, but for total knee arthroplasty the analgesic effectof LIA is overall well-documented, even in combination with multimodal systemicanalgesia.

Previous studies havebeen limited by the lack of comparable systemic analgesia between groups thatreceive LIA and those that don t, the researchers note. There have also beenwide variations in the combinations of LIA techniques and drugs.

Dr. Andersen and Dr.Henrik Kehlet from Copenhagen University critically evaluated the analgesicefficacy of intraoperative LIA in total hip arthroplasty (THA) and total kneearthroplasty (TKA) in a systematic search and review of 27 randomized trials inthe first 72 hours after surgery.

The studies included888 TKA patients and 756 THA patients. Only two of the THA trials wereconsidered to have a low risk of bias; the remaining eight had incompleteblinding or differences in systemic analgesia in the control and interventiongroups. Among the 17 TKA trials, only two were considered to have a low risk ofbias. The others suffered from the same problems as the THA trials with a highrisk of bias.

Seven trials of LIAversus saline or no injection in THA patients showed no significant differencein pain scores when combined with a multimodal systemic analgesic regimen,according to the June 17 British Journal of Anaesthesia report.

In contrast, sevensimilar trials in TKA patients showed reduced pain scores and reduced opioidconsumption in the first 32 hours after surgery in patients who received LIA.

Trials comparing LIAwith peripheral nerve block (PNB) were confounded by the use of differenttechniques of PNB and different systemic analgesias between treatment groups.

The researchers saidthat the high risk of bias in trials comparing LIA with epidural analgesia,systemic analgesia, and intrathecal morphine limited the ability to reachdefinitive conclusions about efficacy.

Similarly, data onhospital length of stay were variable and appeared not to be related to thechoice of analgesic technique in the trials that reported it.

It would behelpful if clinical researchers provided similar analgesics to both/all studygroups - the literature is confounded by administration of various analgesics(NSAID/steroids/opioids, etc.) with the local anesthetic/LIA solution and nocontrol for this was provided in the control group in most studies, Dr.Andersen said. That makes it hard to decide whether intraoperative infiltrationof local anesthetic in high volumes provides better analgesia than thetreatment given to the control group.

In studies onpostoperative pain, there is a need to minimize the confounding factors,because the level of postoperative pain is very different between individuals,so caution on confounding factors should be taken when designing futurestudies, Dr. Andersen said.

Finally, Dr. Andersen said, when assessing the effect of LIA on length of stay(LOS), future studies are required to analyze why is the patient in hospitaltoday, since our review clearly shows insufficient presentation of data and wesummarize that LIA may not influence LOS, which depends on so many otherfactors than pain.