Adductor Canal Block Compared with Periarticular Bupivacaine Injection for Total Knee Arthroplasty: A Prospective Randomized Trial.

BACKGROUND

In the last decade, the widespread use of regional anesthesia in total knee arthroplasty has led to improvements in pain control, more rapid functional recovery, and reductions in the length of the hospital stay. The aim of this study was to compare the efficacy of adductor canal blocks (ACB) and periarticular anesthetic injections (PAI), both with bupivacaine, for pain management in total knee arthroplasty.

METHODS

One hundred and fifty-five patients undergoing primary total knee arthroplasty under spinal anesthesia were randomized to 1 of 3 groups: ACB alone (15 mL of 0.5% bupivacaine), PAI alone (50 mL of 0.25% bupivacaine with epinephrine), and ACB+PAI. The primary outcome in this study was the visual analog scale (VAS) pain score in the immediate postoperative period. Secondary outcomes included postoperative opioid use, activity level during physical therapy, length of hospital stay, and knee range of motion.

RESULTS

The mean VAS pain score was significantly higher after use of ACB alone, compared with the score after use of ACB+PAI, on postoperative day 1 (POD1) (3.9 versus 3.0, p = 0.04) and POD3 (4.2 versus 2.0, p = 0.02). Total opioid consumption through POD3 was significantly higher when ACB alone had been used (131 morphine equivalents [ME]) compared with PAI alone (100 ME, p = 0.02) and ACB+PAI (98 ME, p = 0.02). Opioid consumption in the ACB-alone group was significantly higher than that in the ACB+PAI group on POD2 and POD3 and significantly higher than that in the PAI-alone group on POD2. There was no significant difference in opioid consumption between the patients treated with PAI alone and those who received ACB+PAI. The activity level during physical therapy on POD0 was significantly lower after use of ACB alone (26 steps) than after use of PAI alone (68 steps, p < 0.001) or ACB+PAI (65 steps, p < 0.001).

CONCLUSIONS

This randomized controlled clinical trial demonstrated significantly higher pain scores and opioid consumption after total knee arthroplasty done with an ACB and without PAI, suggesting that ACB alone is inferior for perioperative pain control. There were no significant differences between PAI alone and ACB+PAI with regard to pain or opioid consumption.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.