# Association Between Peripheral Nerve Blocks and Reduced Opioid Rescue Use in the PACU After Knee Surgery: A Retrospective Study From a Mexican Tertiary Center

## TL;DR

This study found that using peripheral nerve blocks during knee surgery reduces the need for opioid pain relief in recovery.

## Contribution

The study provides evidence that peripheral nerve blocks significantly reduce opioid use in the post-anesthesia care unit after knee surgery.

## Key findings

- Opioid rescue was needed by 27.87% of patients without a PNB and 12.90% with a PNB.
- The use of PNBs was associated with a 53.7% relative risk reduction in opioid rescue requirements.

## Abstract

Introduction: Peripheral nerve blocks (PNBs) are increasingly used for multimodal analgesia in knee surgery, yet their impact on opioid use in the recovery room remains understudied. This study aimed to assess the effectiveness of PNBs in being associated with reduced need for opioid rescue in the post-anesthesia care unit (PACU).

Methods: This retrospective cohort study included 123 patients who underwent knee surgery under general anesthesia with or without the addition of a peripheral nerve block. The primary outcome was the requirement of intravenous opioid rescue during PACU stay. Data were analyzed using chi-square and Fisher's exact tests.

Results: Of the total patients, 61 received general anesthesia alone and 62 received general anesthesia plus a PNB. Opioid rescue in the PACU was required in 27.87% of patients without a PNB versus 12.90% with a PNB (p = 0.043, chi-square = 4.09). This corresponds to a relative risk reduction of 53.7%, an absolute risk reduction of 14.97%, and a number needed to treat (NNT) of 7.

Conclusion: The use of peripheral nerve blocks in knee surgery is associated with a significant reduction in the need for opioid rescue in the PACU. These findings support the incorporation of PNBs into standard multimodal analgesia protocols.