The 2012 Chitranjan Ranawat award: intraarticular analgesia after TKA reduces pain: a randomized, double-blinded, placebo-controlled, prospective study

Abstract

Background: Postoperative pain after total knee arthroplasty remains one of the most important challenges facing patients undergoing this surgery. Providing a balance of adequate analgesia while limiting the functional impact of regional anesthesia and minimizing opioid side effects is critical to minimize adverse events and improve patient satisfaction.

Questions/purposes: We asked whether bupivacaine delivered through an elastomeric device decreases the (1) patients' perception of pain after TKA; (2) narcotic consumption; and (3) narcotic-related side effects as compared with a placebo.

Methods: In this prospective, double-blind, placebo-controlled study, all patients received standardized regional anesthesia, a preemptive and multimodal analgesic protocol, and a continuous intraarticular infusion at 5 mL/hour through an elastomeric infusion pump. The patients were randomized to receive either an infusion pump filled with (1) 300 mL of 0.5% bupivacaine, the experimental group (n = 75); or (2) 300 mL of 0.9% normal saline solution, the control group (n = 75). Data concerning postoperative pain levels through a visual analog scale, postoperative opioid consumption, opioid-related side effects, and complications were collected and analyzed.

Results: Patients in the experimental group receiving the bupivacaine reported a reduction in pain levels in highest, lowest, and current visual analog scale scores compared with the placebo group on the first postoperative day and highest visual analog scale score on postoperative Day 2 along with a 33% reduction in opioid consumption on postoperative Day 2 and a 54% reduction on postoperative Day 3.

Conclusion: In patients undergoing TKA, continuous intraarticular analgesia provided an effective adjunct for pain relief in the immediate postoperative period without the disadvantages encountered with other analgesic methods.

Fig. 1

The On-Q PainBuster^® (I-Flow Corp, Lake Forest, CA, USA) elastomeric infusion pump was used in this study.

Fig. 2

The study screening, consent, and enrollment flowchart demonstrates the number of patients who completed the study at each step.

Fig. 3

This figure delineates the preemptive and multimodal analgesic regimen and breakthrough pain medication dosing protocol that was used in the perioperative period for the study. POD = postoperative day; PCA = patient-controlled analgesia; NSAID = nonsteroidal antiinflammatory drug.

Fig. 4

The mean VASs on postoperative Days 1 to 3 are shown here.

Fig. 5

The mean postoperative narcotic consumption on Days 1 to 3 is shown here.