Intra-articular clonidine for post-operative analgesia following arthroscopic knee surgery: a systematic review and meta-analysis

To assess the efficacy and safety of a single dose of intra-articular clonidine for post-operative pain following arthroscopic knee surgery by analyzing relevant randomized controlled trials (RCTs). PubMed, EMBASE, Cochrane Library, ISI Web of knowledge, Chinese Biomedical Literature Database, Google Scholar and other databases were searched for RCTs comparing a single dose of intra-articular clonidine with placebo for post-operative pain following arthroscopic knee surgery. Risk of bias of included studies was assessed by Cochrane Collaboration's tool, and data were analyzed by RevMan 5.1 software. Pain intensity, supplementary analgesic use and side effects were evaluated as the outcomes. Seven RCTs were included, and the results of the meta-analysis showed that intra-articular clonidine reduced the pain intensity for the first 4 h after surgery, reduced the risk of using rescue analgesics and the incidence of post-operative nausea, but increased the risk of hypotension after surgery. A single dose of intra-articular clonidine has a definite analgesic effect, but the analgesic effect is mild and short lasting, which is just for 4 h after injection, and intra-articular clonidine alone could not provide sufficient post-operative analgesia following arthroscopic knee surgery. Post-operative hypotension may be the side effect that should be paid the most attention in the ambulatory setting. II.