Effect of intra-articular alpha-agonists on post-operative outcomes following arthroscopic knee surgery: a systematic review and meta-analysis
Perritt, E., Wallace, H, Singh S and Banerjee, A.
 
ABSTRACT
BACKGROUND AND OBJECTIVES
Arthroscopic knee surgery is associated with significant post-operative pain. Intra-articular (IA) infiltration of local anaesthetics (LA) may prolong the duration of analgesia, and there has been extensive investigation into the addition of adjuncts to improve the efficacy of block. The intra-articular alpha-agonists clonidine and dexmedetomidine have been shown to prolong the duration of action of analgesia, but the evidence is limited. The objectives of this systematic review and meta-analysis were to review the available evidence and evaluate the analgesic effect of addition of alpha-agonists to LA when used for arthroscopic knee surgery.
METHODS
PubMed, EMBASE, Cochrane Library, Google Scholar, conference abstracts and bibliographic references were searched for RCTs comparing IA LA to IA LA+ adjuvant, in arthroscopic knee surgery. The data were analysed using RevMan software. The primary outcome was the duration of analgesia, as determined by the time to first request for additional analgesia in the post-operative period. Secondary outcomes were pain intensity, total opiate consumption over 24 hours and incidence of cardiovascular disturbance.
RESULTS
Seven trials (340 patients) were included in the meta-analysis. Alpha-agonists significantly prolonged the duration of action of LA [SMD 2.69 [95% CI, 2.30 to 3.08] (p<0.00001)]. VAS scores at rest were significantly lower at two hours (SMD -0.83 [95% CI, -1.22, -0.44](p<0.0001)] when alpha-agonists were used. Furthermore, total opiate consumption was reduced in the experimental group (SMD -1.78 [95% CI, -2.48, -1.09] (p<0.00001)]. Adverse effects were minimal with no significant differences seen between groups.
CONCLUSIONS
Intra-articular infiltration of alpha-agonists with LA significantly prolongs duration of analgesia and reduces pain intensity following arthroscopic knee surgery.