Proximal versus distal adductor canal catheters for total knee arthroplasty: a systematic review and meta-analysis of randomized controlled trials

Abstract

Purpose: Total knee arthroplasty (TKA) is associated with severe postoperative pain. Continuous adductor canal blockade provides analgesia while preserving quadriceps muscle strength. Nevertheless, uncertainty still exists as to the optimal adductor canal catheter placement approach. We sought to conduct a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing the analgesic effects of proximal vs distal adductor canal catheters in patients undergoing TKA. Source: We systematically searched PubMed, EMBASE, and Cochrane for RCTs comparing distal and proximal adductor canal catheters for TKA regarding critical clinical outcomes in adult patients. Statistical analysis was performed using R version 4.1.2 (R Foundation for Statistical Computing, Vienna, Austria). Heterogeneity was assessed using the Cochran Q test and I2 statistics. Trial sequential analysis (TSA) was performed to evaluate the risk of random errors and the uncertainty of our results. The risk of bias was appraised according to the RoB-2 tool. Principal findings: Six RCTs and 352 patients were included, of whom 151 (42.9%) were male, and 175 (49.7%) were randomized to undergo proximal adductor canal catheter placement. Due to the randomized nature of the studies, baseline characteristics were similar between groups. There were no statistical differences between proximal and distal adductor canal catheters regarding cumulative opioid consumption in the first 24 hr (mean difference [MD], −4.86; 95% confidence interval [CI], −15.19 to 5.47; P = 0.36; four RCTs; 240 patients); pain scores at rest (MD, 0.41; 95% CI, −1.23 to 0.40; P = 0.32; six RCTs; 350 patients); and pain scores with movement for the first 24 hr (MD, −0.25; 95% CI, −0.85 to 0.35; P = 0.42; four RCTs; 246 patients). In the TSA, the required information size was not reached, and the Z-curve did not cross the monitoring boundaries in any of the endpoints. Conclusion: These findings suggest that proximal vs distal adductor canal catheter placement in patients undergoing TKA may be equally effective for the outcomes of opioid consumption in the first 24 hr, pain scores at rest, and pain scores with movement in the first 24 hr. Nevertheless, TSA findings suggest insufficient power to definitively conclude no differences between the two techniques. Study registration: PROSPERO (CRD42022353576); registered 25 August 2022.