In a study conducted by researchers at Hospital for Special Surgery (HSS), the addition of periarticular injection (PAI) of local anesthetic by surgeons did not appear to reduce pain during ambulation after total knee arthroplasty, nor did it reduce opioid use, in patients who underwent a multimodal analgesia protocol that included an adductor canal block (ACB) and Infiltration between the Popliteal Artery and Capsule of the Knee (IPACK) block. These findings were presented at the 2022 Spring American Society of Regional Anesthesia and Pain Medicine (ASRA) Annual Meeting.¹

“If not properly treated, pain after TKA can be severe. Currently, in addition to other analgesic medications (multimodal analgesia), many patients receive two long-lasting nerve blocks (ACB and IPACK) as well as PAI by the surgical staff,” said HSS anesthesiologist Jacques Ya Deau, MD, PhD. “Previous studies have shown that patients with a PAI do better when the nerve blocks are added to their pain management therapy.”

However, “we thought that it may not be necessary to do the PAI, given the theoretically nearly-complete analgesia provided by the two nerve blocks. It's best to avoid unnecessary procedures,” Dr. Ya Deau added.

The researchers randomized 94 patients undergoing primary TKA into either a PAI group or a placebo group. Patients in the PAI group received a deep injection consisting of: 

• 30 mL of bupivacaine 0.25%, with 1:200,000 epinephrine
• 8 mg of Morphine
• 40 mg of Methylprednisolone
• 500 mg of Cefazolin
• Normal saline to bring total volume to 64 mL

They also received a superficial injection of 20 mL of bupivacaine, 0.25%.

Both groups received the standardized multimodal analgesia protocol of intraoperative sedation consisting of: 

• midazolam and propofol
• a mepivacaine spinal (60 mg)
• adductor canal block (comprised of 15 mL bupivacaine 0.25%, with 1 mg of preservative-free dexamethasone)
• IPACK block (comprised of 25 mL bupivacaine 0.25%, with 2 mg of preservative-free dexamethasone)
• intraoperative ketamine (50 mg)
• ketorolac (15 mg)

Postsurgical pain relief included:

• IV ketorolac, followed by oral meloxicam
• IV, then oral acetaminophen
• 60 mg of oral duloxetine daily
• 5-10 mg of oral oxycodone by mouth every 4 hours as needed. Opioids were adjusted according to patient needs. 
• In the recovery room, IV hydromorphone was available for breakthrough pain. 

The researchers examined numerical rating score (NRS) pain with movement and opioid consumption. They found no significant difference between the PAI and placebo groups. NRS pain with movement the day after surgery in the ACB/IPACK/No PAI group was noninferior to the ACB/IPACK/PAI group, and there was no significant difference in cumulative opioid consumption from the PACU to postop day 2 between the groups. 

These results indicate that PAI may not provide a benefit in patients undergoing TKA with a multimodal pain relief plan that already includes ACB and IPACK blocks. “In the context of multimodal analgesia, the two nerve blocks provided excellent pain relief. There was no additional benefit from adding a PAI,” Dr. Ya Deau said. 

The researchers noted that these results may not be generalizable to different surgeries or to patients with different underlying conditions or baseline characteristics. 

Dr. Ya Deau added that looking towards future research, it is important to investigate how to improve pain relief after the nerve blocks wear off a few days after surgery.

“Currently, most TKA patients have excellent pain relief during the first few days. This is the acute pain phase, when otherwise pain would be most severe,” Dr. Ya Deau said. “Unfortunately, some of these patients have more pain than is desirable once discharged. We need to continue trying to improve pain management on days 3-14 after surgery,” he concluded.

Reference

1. Justas Lauzadis, PhD; Douglas Padgett, MD; Geoffrey Westrich, MD; Ejiro Gbaje, MPH; Fred Cushner, MD; Richard L. Kahn, MD; Yi Li n, MD; Enrique A. Goytizolo, MD; David J Mayman, MD; David H. Kim, MD; Kethy M. Jules Elysee, MD; Jacques T. YaDeau , MD, PhD. “Does Periarticular Injection reduce pain after knee arthroplasty among patients receiving peripheral nerve blocks?” Presented at: 47th Annual Regional Anesthesiology and Acute Pain Medicine Meeting of the American Society of Regional Anesthesia and Pain Medicine (ASRA), March 31-April 2, 2021; Las Vegas, NV.