# Analgesic efficacy of blocking nerve to vastus lateralis muscle versus lateral femoral cutaneous nerve after knee surgeries: a randomized trial

## TL;DR

This study compares two nerve blocks for pain management after knee surgeries, finding one provides faster pain relief with less opioid use.

## Contribution

The study introduces the nerve to vastus lateralis block as a promising alternative to the lateral femoral cutaneous nerve block for postoperative pain control.

## Key findings

- The NVL block had faster sensory onset and reduced opioid consumption compared to the LFCN block.
- Both blocks provided comparable pain control and patient satisfaction with no major side effects.
- NVL block did not significantly improve overall pain control despite faster onset and less opioid use.

## Abstract

Postoperative pain is common following knee surgeries. Effective pain management is crucial for speeding up recovery, improving satisfaction for patients, and reducing the risk of complications. This research aimed to assess analgesic effectiveness and functional outcomes of blocking the nerve to the vastus lateralis (NVL) muscle versus the lateral femoral cutaneous nerve (LFCN).

This randomized, double-blind study was carried out on 80 patients aged ≥ 18 years, both sexes, who underwent knee surgeries under spinal anesthesia using 15 mg of bupivacaine 0.5%. Patients were allocated to two equal groups: Group VL was given the NVL block, and Group LFCN received the LFCN block. Blocks were performed at the surgical ending under ultrasound guidance with 5 ml of 0.5% bupivacaine. The primary outcome was the numerical rating score.

Time of onset of sensory block and time required to achieve the maximum sensory block, pain scores at 4, 6, and 12 h postoperatively, and total morphine consumption were significantly lower, while time to the first request for rescue analgesia was significantly postponed in Group NVL compared to Group LFCN (P < 0.001). Patient satisfaction, side effects, and hospital stay lengths were similar between both groups, with no cases of respiratory depression or local anesthetic toxicity.

The NVL block may serve as a potential alternative to the LFCN block for postoperative analgesia in knee surgeries, as both techniques provided comparable postoperative pain control and were safe and well tolerated, while the faster sensory onset and reduced opioid consumption associated with the NVL block did not translate into a meaningful improvement in pain control.

Registered at clinicaltrials.gov (ID: NCT06809842, Date of registration: 30/01/2025, URL: https://clinicaltrials.gov/study/NCT06809842?cond=NCT06809842&rank=1).