There's a straightforward way to reduce the number of complications following total knee replacements and improve the recoveries of patients who undergo these notoriously painful procedures: Stop relying on opioids to provide pain relief.

It's been know for years that opioid-related side effects — PONV, constipation, sedation and respiratory depression — limit short-term recovery from total knees. Providers and patients are now becoming increasingly aware of the long-term negative effects of using opioids to manage post-op pain. For example, approximately 6% of opioid-na??ve patients will still be taking the painkillers up to 6 months after surgery, according to Ellen M. Soffin, MD, PhD, an anesthesiologist at the Hospital for Special Surgery in New York City.

The trend to go "opioid-free" sounds like a worthwhile goal to manage the post-op pain of total knee patients and reduce their risk of long-term opioid dependence, but you don't need to totally eliminate the use of opioids to enhance recoveries. Focus on opioid-sparing techniques instead of trying to eliminate their use altogether, suggests Girish P. Joshi, MBBS, MD, FFARCSI, a professor of anesthesiology and pain management at the University of Texas Southwestern Medical Center in Dallas.

"Studies have shown that the judicious use of intraoperative opioids can be beneficial to a multimodal pain management plan," he says. "The primary aim is to use less opioids than you used before."

Accomplishing that goal requires your anesthesia team to target and block sensory nerves and administer non-opioid analgesic agents.

Several years ago, providers learned to reduce pain after total knee arthroplasty for the initial 24 hours post-op through the use of peripheral nerve blocks, local infiltration analgesia and multimodal pain relief. "But when the blocks wore off, patients were uncomfortable, and often had sudden high requirements for opioids to treat breakthrough pain," says Dr. Soffin.

Now, the goal is to find ways to take these techniques to the next level by extending the duration of pain relief without the use of opioids.

"One solution has been to add an adjuvant, like steroids, to local anesthetics," says Dr. Soffin. "Extended duration formulations of local anesthetics are also increasingly being applied to total knee arthroplasty, but their cost relative to outcome benefits remains to be fully established."

She points out that cooled radiofrequency ablation techniques have emerged as a potential option to denervate sensory nerves supplying the knee before patients have the joint replaced. Some facilities are also using continuous peripheral nerve blocks, which involve infusing a local anesthetic at the surgical site over several days using a catheter system and pain pump.

Dr. Joshi, though, urges caution regarding the use of continues nerve blocks. He says they're a good option for pain control in other surgeries, but are a risky option for total knee replacement patients, who must ambulate shortly after the procedure. Instead, Dr. Joshi recommends using peripheral nerve blocks — typically adductor canal blocks, iPACK blocks or surgical site infiltration. He says peripheral nerve blocks should be placed using ultrasound guidance to provide targeted and theoretically more effective pain relief.

Dr. Soffin also acknowledges the risk of using continuous nerve blocks for this patient population, and notes where the catheter is placed can make a difference in the analgesic effects and safe use of the blocks.

"Data supports continuous femoral plus sciatic nerve catheters as profoundly analgesic and opioid-sparing after knee replacements," she says.

"However, the analgesia that can be achieved may come at the cost of safe ambulation and meeting physical therapy discharge goals, since these anatomic sites of blockade can cause motor weakness. For these reasons, adductor canal catheters have become the preferred method."

Combined effort

Non-opioid analgesics are another key component of an opioid-sparing approach to pain management. An effective multimodal regimen could include:

• Preoperatively. Acetaminophen 1 gm PO + celecoxib 400 mg PO (If available. If not, use an NSAID intraoperatively). Use in combination with a regional analgesia option such as an adductor canal or iPACK block.
• Intraoperatively. Acetaminophen 1 gm IV (if not given orally in the preoperative period) and ketorolac 15 to 30 mg IV (if celecoxib is not given preoperatively) if there are no contraindications. A regional analgesia option includes surgical site infiltration.
• Postoperatively. Acetaminophen 1 gm PO/q 6h + celecoxib 200 mg PO/q12h or meloxicam 15 mg PO once a day (or any other NSAID of choice). Oxycodone as needed for breakthrough pain.

Dr. Joshi says acetaminophen and a non-steroidal anti-inflammatory drug (NSAID) or a COX-2 specific inhibitor should be administered unless there are contraindications, and they must be given round the clock as scheduled dosing. The guiding principle of your multimodal regimen should be that the medications are acting at different sites in the central and peripheral nervous systems. This creates a synergistic effect on pain control while minimizing the side effects associated with any individual agent, says Dr. Soffin.

Her standard multimodal pain management regimen includes local anesthetic-based techniques (peripheral nerve blocks and catheters), acetaminophen and an NSAID. A gabapentinoid may also be effective, depending on the patient's condition and comorbidities, according to Dr. Soffin.

"Although caution with polypharmacy should be stressed — particularly in elderly patents," she says, "perioperative ketamine is increasingly being applied to total knee anesthetic and analgesic regimens, particularly for patients with chronic pain conditions."

Exercise caution if you add a gabapentin to your multimodal regimen. According to Dr. Soffin, the risks of gabapentin in older age on sedation and respiratory depression are established — particularly if combined with an opioid.

"Total knee arthroplasty is highly amenable to long-lasting regional analgesia techniques," she says. "We may find a ceiling effect, whereby individual agents like gabapentin do not have additional benefits on pain control over and above those produced with effective nerve blocks plus acetaminophen and NSAIDs."

Moving closer to zero

Dr. Joshi notes that although the overall goal is to reduce the use of opioids, you still will likely need to include some in the multimodal regimen for total knee patients. The key is to make sure they're not overprescribed, which was one of the causes of the opioid epidemic. Instead, be sure your providers are choosing the lowest dose for the shortest duration possible.

Drs. Joshi and Soffin agree that reducing the overall number of opioids prescribed after surgery requires educating patients on your expectations for their post-op recoveries and establishing realistic expectations of the pain they'll experience.

"Patients need to have a realistic approach to surgery," says Dr. Joshi. "They should know that some pain is normal, and that it will gradually get better. Taking opioids for soreness is inappropriate. Patients must understand they're undergoing a major surgery — so you cannot completely eliminate their pain."

Some facilities might lack the necessary resources to adopt opioid-free total knee arthroplasty, says Dr. Soffin.

"But rather than abandon the goal entirely, they can implement an incremental approach," she adds. "Elements of an opioid-sparing approach should be achievable, and they will help to protect patients and improve outcomes." OSM

Non-opioid analgesics are another key component of an opioid-sparing approach to pain management. An effective multimodal regimen could include:

• Preoperatively. Acetaminophen 1 gm PO + celecoxib 400 mg PO (If available. If not, use an NSAID intraoperatively). Use in combination with a regional analgesia option such as an adductor canal or iPACK block.
• Intraoperatively. Acetaminophen 1 gm IV (if not given orally in the preoperative period) and ketorolac 15 to 30 mg IV (if celecoxib is not given preoperatively) if there are no contraindications. A regional analgesia option includes surgical site infiltration.
• Postoperatively. Acetaminophen 1 gm PO/q 6h + celecoxib 200 mg PO/q12h or meloxicam 15 mg PO once a day (or any other NSAID of choice). Oxycodone as needed for breakthrough pain.