The effects of continuous catheter adductor canal block for pain management in knee replacement therapy: a meta-analysis.

Purpose: Adductor canal block has emerged as a favourable element of multimodal analgesia regimens for total knee arthroplasty, due to the exclusive sensory blockade it provides. However, it is controversial as to whether a single shot or continuous technique adductor canal block is superior. This meta-analysis examined the effect of both these techniques on pain management associated with total knee arthroplasty.

Methods: All randomised controlled trials published on Cochrane Library, PubMed, and EMBASE, Scopus, and PsychINFO were systematically searched. The PEDro scale was used to assess the quality of studies. A total of 8 articles, 2 of which were split by subgroup analyses to create 10 studies, with 828 adults were selected for inclusion in the analysis. The mean difference and effect size with a 95% confidence interval (CI) were analysed for the pooled results.

Results: Statistically significant pooled effects of analgesia technique in favour of catheter use were found in the reduction of pain scores and VAS scores, and total rescue analgesia dosage. No significant changes were observed in the hospital stay time. Subgroup analysis revealed that patients with BMI 30 or more reported higher pain scores than those with BMI below 30.

Conclusion: Based upon studies that are currently available, our meta-analysis appears to demonstrate that continuous administration of analgesia through an adductor canal catheter provides greater pain reduction in total knee arthroplasty than single shot analgesia. Despite these current findings, future studies with larger sample sizes and greater control of study parameters are required to confirm the current findings.