# A Comparison Between Ultrasound-Guided Adductor Canal Block and Intra-articular Injection With Ropivacaine and Clonidine Combination for Postoperative Analgesia After Arthroscopic Knee Procedures: A Randomized, Double-Blind Clinical Study

## TL;DR

This study compares two pain management techniques after knee arthroscopy and finds that an ultrasound-guided adductor canal block provides longer pain relief than an intra-articular injection.

## Contribution

The study provides empirical evidence that ultrasound-guided adductor canal block offers superior postoperative analgesia compared to intra-articular injection with the same drug combination.

## Key findings

- ACB group had a significantly longer time to first pain (385.50 minutes) compared to the IAA group (311.00 minutes).
- ACB group required rescue analgesia later (478.00 minutes) than the IAA group (341.50 minutes).
- ACB provided prolonged pain relief, reduced rescue analgesia need, and maintained hemodynamic stability.

## Abstract

Background and objective

In recent years, arthroscopic procedures have gained significant popularity due to their distinct advantages, including minimal invasiveness, reduced postoperative scarring, quicker recovery, and lower surgical risks. However, inadequate postoperative pain control following orthopedic surgeries can hinder early mobilization, delay rehabilitation, and prolong hospital stays. The adductor canal block (ACB) has emerged as a favorable option for postoperative analgesia in such cases, offering benefits like ease of administration, cost-effectiveness, and compatibility with both general and spinal anesthesia. Likewise, intra-articular analgesia (IAA) is another effective method for managing postoperative pain. In this study, we compared the efficacy of ACB with intra-articular injection of a combination of ropivacaine and clonidine in patients undergoing arthroscopic procedures.

Methodology

Forty American Society of Anesthesiologists (ASA) physical status I/II adult patients were randomized into two groups (n=40). Group A received an ACB with 20 ml of 0.25% ropivacaine and 30 mcg clonidine, while Group B received an intra-articular injection with 20 ml of 0.25% ropivacaine with 30 mcg clonidine under ultrasound guidance after the ACB. Postoperative pain and duration of analgesia were assessed.

Results

Demographic and hemodynamic parameters were comparable between the two groups. However, there was a statistically significant difference in the time to first pain and the time to first rescue analgesia requirement. The mean time to first pain was 385.50 ± 44.90 minutes in the ACB group, compared to 311.00 ± 25.53 minutes in the IAA group (p<0.001). Similarly, the mean time to the first request for rescue analgesia was significantly longer in the ACB group (478.00 ± 36.22 minutes) compared to the IAA group (341.50 ± 24.12 minutes, p<0.001).

Conclusions

ACB using 0.25% ropivacaine combined with 30 mcg of clonidine provided superior postoperative analgesia compared to intra-articular injection with the same drug combination. It was associated with prolonged pain relief, a reduced need for rescue analgesia, earlier restoration of postoperative function, and maintained hemodynamic stability. The choice between these techniques can be individualized based on patient-specific factors, institutional guidelines, and availability of resources.