Combined proximal or distal nerve blocks for postoperative analgesia after total knee arthroplasty: a randomised controlled trial.

BACKGROUND

Many regional anaesthetic techniques have been proposed to manage pain after total knee arthroplasty, but the best approach is unclear. We compared opioid consumption in the first 48 h between two different regional anaesthesia strategies in patients undergoing total knee arthroplasty.

METHODS

In this single-centre, prospective study, we randomly allocated 90 patients to a combination of IPACK (interspace between popliteal artery and capsule of the posterior knee), triangle femoral and obturator nerve blocks (distal group), or a combination of sciatic, femoral, obturator, and lateral femoral cutaneous nerve blocks (proximal group). All patients received an opioid-sparing general anaesthesia regimen. The primary outcome was opioid consumption in the first 48 h. Secondary outcomes included opioid consumption in the first 24 h and verbal rating pain scores in the first 48 h.

RESULTS

There was no difference in median cumulative oral morphine equivalent consumption at 48 h between the distal and the proximal block groups (33 [18-78] mg vs 30 [22-51] mg, respectively; P=0.29). Median oral morphine equivalent consumption at 24 h was higher in the distal group compared with the proximal group (30 [13-59] vs 15 [0-18], respectively; P<0.001). Verbal rating pain scores were lower in the proximal group compared with the distal group on arrival to the postanaesthesia care unit and at 6 and 12 h.

CONCLUSIONS

In patients undergoing total knee arthroplasty under total intravenous general anaesthesia with a multimodal analgesia regimen, proximal nerve blocks resulted in improved pain scores in the first 12 h and reduced opioid consumption in the first 24 h when compared with distal nerve blocks. No difference in pain scores or opioid consumption was seen at 48 h.

CLINICAL TRIAL REGISTRATION

NCT04499716.