# Effects of single femoral nerve block and continuous femoral nerve block on perioperative analgesia and muscle strength in elderly patients undergoing total knee arthroplasty, a randomized clinical trial

## TL;DR

This study compares single and continuous femoral nerve blocks for pain and muscle strength in elderly patients after knee surgery, finding similar pain relief but better muscle strength and comfort with the single block.

## Contribution

The study introduces evidence that single femoral nerve block offers comparable pain management with improved muscle strength and comfort compared to continuous block in elderly TKA patients.

## Key findings

- SFNB group showed higher muscle strength scores at 6h, 12h, and 24h postoperatively compared to CFNB.
- SFNB provided better knee range of motion and higher GCQ scores without increased adverse effects.
- No significant differences in pain scores or celecoxib dosage between the two groups.

## Abstract

To investigate the effect of single femoral nerve block (SFNB) with 0.2% ropivacaine 50 ml on postoperative pain and muscle strength in elderly patients undergoing knee replacement.

Ninety-four patients scheduled for primary total knee arthroplasty (TKA) were randomized into two groups. The patients in the SFNB group received SFNB with 50 ml 0.2% ropivacaine (n = 48), while the patients in the continuous femoral nerve block (CFNB) group (n = 46) received CFNB with an initial load of 20 ml 0.5% ropivacaine and a continuous injection of 0.2% ropivacaine at a rate of 5 ml/h. After the surgery, all patients were administered patient-controlled intravenous analgesia. The primary outcome was the visual analogue scale (VAS) score at 24 h postoperatively. The secondary outcomes included: (a) Pain scores at 2 h, 6 h, 12 h, 48 h, and 72 h after surgery, and the total dosage of celecoxib; (b) Muscle strength of the quadriceps at 2 h, 6 h, 12 h, 24 h, 48 h, and 72 h postoperatively; (c) Range of motion (ROM) at 24 h, 72 h, and 1 week after surgery; (d) American Knee Society knee score (AKS) at 1 week postoperatively; (e) Related complications (e.g., nausea and vomiting), and length of hospitalization; (f) General Comfort Questionnaire (GCQ) score at 72 h postoperatively.

(a) There were no statistically significant differences in VAS scores (p > 0.05) or the total dosage of celecoxib (p > 0.05) between the two groups at various time points; (b) The muscle strength scores in the SFNB group were higher than those in the CFNB group (p < 0.05) at 6 h, 12 h, and 24 h postoperatively; (c) Knee ROM in the SFNB group was better than in the CFNB group (p < 0.05); (d) There were no significant differences in adverse events between the two groups (p > 0.05); (e) The physiological and psychological scores on the GCQ in the SFNB group were higher than those in the CFNB group (p < 0.05).

SFNB, with 0.2% ropivacaine 50 ml provides effective pain relief, and improves patient comfort after surgery, without increasing adverse effects. SFNB is a safe and convenient option for postoperative pain management following knee surgery.