Continuous block at the proximal end of the adductor canal provides better analgesia compared to that at the middle of the canal after total knee arthroplasty: a randomized, double-blind, controlled trial

Does Proximal Adductor Canal Block Provide Better Analgesic Efficacy than Distal Adductor Canal Block in Patients Undergoing Knee Arthroplasty: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

To compare the analgesic efficacy and adverse events of proximal versus distal ACB for adults undergoing knee arthroplasty, we searched PubMed, Cochrane, Web of Science, and Embase to identify all eligible randomized controlled trials (RCTs). The study quality of the RCTs was evaluated using the Cochrane risk of bias assessment tool. Heterogeneity among studies was examined by Cochrane Q test. Our primary outcomes were pain intensity at rest/during movement and morphine consumption. Statistical analyses were conducted by RevMan Software. Seven eligible studies involving 400 subjects were included in this meta-analysis with 202 participants in the proximal ACB group and 198 participants in the distal ACB group. The results demonstrated that proximal ACB provided significantly better pain relief at rest at 2 h (SMD -0.27, 95% CI -0.54 to -0.01, four trials, 222 participants, I2 = 0, p = 0.04) and 24 h (SMD -0.28, 95% CI -0.48 to -0.08, seven trials, 400 participants, I2 = 0, p = 0.006) following the surgery. We found no evidence of a difference in postoperative pain intensity at other timepoints. Furthermore, we noted no evidence of a difference in cumulative morphine consumption and occurrence of adverse events. Proximal ACB provides better pain relief and comparable adverse effects profile compared with distal ACB. The analgesic benefit offered by proximal ACB, however, did not appear to extend beyond the first 24 h. The overall evidence level was mostly low or very low, which requires more well-organized multicenter randomized trials in the future.

Bibliometric and visual analysis of research on analgesia and total knee arthroplasty from 1990 to 2022

Background

In recent decades, there have been notable advancements in the field of analgesia and total knee arthroplasty (TKA). This study aims to employ bibliometric analysis to elucidate the prevailing research focal points and trends within analgesia and TKA from 1990 to 2022.

Material and methods

Relevant publications were retrieved from the Web of Science Core Collection. CiteSpace, VOSviewer, and Scimago Graphica were used for visualization and bibliometric analysis of countries, institutions, authors, journals, references, and keywords.

Results

A total of 2776 publications on analgesia and TKA were identified, with the United States having the highest number of publications. The University of Copenhagen was the most productive institution, and Kehlet, Henrik was the most prolific author. The Journal of Arthroplasty had the most publications and citations. The most common keywords were "TKA," "pain management," "postoperative pain," "Total hip arthroplasty (THA)," and "postoperative management." Keyword burst detection demonstrated that adductor canal block (ACB) was a recent research hotspot.

Conclusion

Our study revealed a sharp increase in global publications on analgesia and TKA, and this trend is expected to continue. Further research is necessary to determine the optimal regimen for multimodal analgesia, the ideal location and volume of ACB, and their clinical significance.

Distal subsartorial compartment block of the saphenous nerve - A dissection study and a patient case series

STUDY OBJECTIVE

A saphenous nerve block is an important tool for analgesia after foot and ankle surgery. The conventional midthigh approach to saphenous nerve block in the femoral triangle may impede ambulation by impairing quadriceps motor function.

PRIMARY OBJECTIVE

Developing a selective saphenous nerve block targeting the nerve distal to its emergence from the adductor canal in the subsartorial compartment.

DESIGN

This study consists of A) a dissection study and B) Data from a clinical case series.

SETTING

A) Medical University of Innsbruck, Austria (dissection of 15 cadaver sides) and. B) Aarhus University Hospital, Denmark (5 patients).

INTERVENTIONS

A) Five mL of methylene blue was injected into the subsartorial compartment distal to the intersection of the saphenous nerve and the tendon of the adductor magnus guided by ultrasound. B) Five patients undergoing major hindfoot and ankle surgery had a subsartorial compartment block with 10 mL of local anesthetic in addition to a popliteal sciatic nerve block.

MEASUREMENT

A) The frequencies of staining the saphenous and medial vastus nerves. B) Assessment of postoperative pain by NRS score (0-10) and success rate of saphenous nerve block by presence of cutaneous anesthesia in the anteromedial lower leg, and motor impairment by ability to ambulate.

MAIN RESULTS

A) The saphenous nerve was stained in 15/15 cadaver sides. A terminal branch of the medial vastus nerve was stained in 2/15 cadaver sides. B) All patients were fully able to ambulate without support. No patients had any post-surgical pain from the anteromedial aspect of the ankle and foot (NRS score 0). The success rate of saphenous nerve block was 100%.

CONCLUSION

The saphenous nerve can be targeted in the subsartorial compartment distal to the intersection of the nerve and the tendon of the adductor magnus. The subsartorial compartment block provided efficient analgesia without quadriceps motor impairment.

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

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.

[Research progress on analgesic effect of adductor canal block after knee arthroplasty]

Objective

To summarize the research progress of the analgesic effect of adductor canal block (ACB) applied to knee arthroplasty, in order to find the ACB mode that can obtain better effectiveness.

Methods

The research progress of the analgesic effect of ACB after knee arthroplasty was reviewed by widely consulting the related literature on ACB at home and abroad in recent years.

Results

In recent years, multimodal analgesia has become the mainstay of postoperative pain management after knee arthroplasty. Among these, ACB replaces the once "gold standard" femoral nerve block (FNB) by offering comparable and effective analgesia with better preservation of quadriceps function. It is generally safe and efficient to use 0.2% ropivacaine ACB with initial loading doses of 15-30 mL and continual loading doses of less than 8 mL/hour to give analgesia comparable to FNB with minimal impact on lower extremity muscular strength. However, the risk of patient falls must still be taken into consideration by medical staff. Adjuvants like dexmedetomidine and dexamethasone used in ACB can increase the analgesic duration and postoperative analgesic impact. As a perineural adjunct for ACB, 1 µg/kg dexmedetomidine may strike a balance between safety and analgesic efficacy.

Conclusion

ACB is a safe and effective analgesia method after knee arthroplasty. The adductor canal anatomy, the optimum blocking strategy and blocking site of ACB are all hotly debated and still require additional study due to the significant variety of the nerve structures in adductor canal.

Optimal location for continuous catheter analgesia among the femoral triangle, proximal, or distal adductor canal after total knee arthroplasty: a randomized double-blind controlled trial

Background

Pain management after total knee arthroplasty is essential to improve early mobilization, rehabilitation, and recovery. Continuous adductor canal (AC) block provides postoperative analgesia while preserving quadriceps strength. However, there have been inconsistencies regarding the optimal location for continuous catheter block. We compared continuous femoral triangle, proximal AC, and distal AC blocks for postoperative analgesia after total knee arthroplasty.

Methods

Patients undergoing unilateral total knee arthroplasty were randomly assigned to three groups: femoral triangle, proximal AC, or distal AC. The surgeon performed periarticular local anesthetic infiltration. After surgery, an ultrasound-guided perineural catheter insertion procedure was performed. The primary endpoint was pain scores at rest in the morning on the first postoperative day. Secondary endpoints included pain scores at rest and during activity at other time points, quadriceps strength, and opioid consumption.

Results

Ninety-five patients, 32 in the femoral triangle group, 31 in the proximal AC group, and 32 in the distal AC group, completed the study. Analysis of the primary outcome showed no significant difference in pain scores among groups. Secondary outcomes showed significantly lower pain scores at rest and during activity in the distal AC group than in the femoral triangle and proximal AC groups in the morning of the second postoperative day. Quadriceps strength and opioid consumption did not differ among groups.

Conclusions

Continuous femoral triangle, proximal AC, and distal AC blocks in the setting of periarticular local anesthetic infiltration provide comparable postoperative analgesia after total knee arthroplasty.

Trial registration number

NCT04206150.