What is a recommended pain management regimen for total knee arthroplasty (TKA)?

Pain Management Regimen for Total Knee Arthroplasty

The optimal pain regimen for TKA consists of multimodal analgesia with scheduled paracetamol and NSAIDs/COX-2 inhibitors, combined with adductor canal block and periarticular local infiltration analgesia, plus intravenous dexamethasone, with opioids reserved only for breakthrough pain. 1

Primary Regional Anesthesia Approach

Choose one of these two primary techniques:

• General anesthesia combined with adductor canal block is the preferred primary technique for surgery and postoperative analgesia 2
• Alternatively, spinal anesthesia with local anesthetic plus intrathecal morphine 0.1 mg can be effectively used 3, 2

For the adductor canal block specifically, continuous catheter technique is preferred over single-shot injection for extended analgesia 2

Multimodal Baseline Analgesics (Start Pre-operatively or Intra-operatively)

All patients should receive this foundation:

• Paracetamol (acetaminophen) administered on a scheduled basis, not as-needed 3, 2, 1
• Conventional NSAIDs or COX-2-selective inhibitors unless contraindicated 3, 2, 1
• Single intra-operative dose of intravenous dexamethasone 8-10 mg for analgesic and anti-emetic effects 3, 1

Additional Regional Technique

Add periarticular local infiltration analgesia at the surgical site 1

Adjunctive Non-Pharmacologic Measures

Implement cooling and compression techniques to reduce local inflammation and pain 2, 4

Rescue Analgesia Protocol

Opioids should be reserved strictly as rescue analgesics in the postoperative period, not scheduled 3, 2, 1

• For high-intensity breakthrough pain: use intravenous strong opioids 3, 2
• For moderate to low-intensity pain: use weak opioids 3, 2

What NOT to Do: Common Pitfalls

Avoid these interventions due to lack of benefit or increased risk:

• Do NOT use epidural analgesia - it increases risk of serious adverse events without superior benefits compared to peripheral nerve blocks 2, 4
• Do NOT combine femoral and sciatic nerve blocks - limited and inconsistent evidence, no proven benefit over adductor canal block alone 3, 2, 4
• Do NOT use intra-articular NSAIDs, neostigmine, clonidine, or corticosteroids - inconsistent transferable evidence 3
• Do NOT use spinal clonidine or spinal neostigmine - limited evidence and significant side effects 3
• Do NOT use adjuvant peripheral nerve drugs like alpha-2-adrenoceptor agonists (clonidine, epinephrine) - lack of efficacy 3

Special Consideration: Intrathecal Morphine

Intrathecal morphine 0.1 mg may be considered ONLY in rare hospitalized situations when both adductor canal block and local infiltration analgesia are not possible 1. However, this comes with significant caveats regarding risks and side effects, and adequate analgesia can typically be achieved without it using the basic analgesics and regional techniques described above 3

Critical Timing Consideration

Ensure proper timing of adductor canal block administration to provide adequate analgesic effect in the immediate postoperative period 2

Special Population: Bilateral TKA

When performing bilateral adductor canal blocks for bilateral TKA:

• Reduce the total dose of local anesthetic to minimize risk of systemic toxicity 2, 4
• Be particularly cautious in elderly patients or those with significant comorbidities due to increased risk of local anesthetic systemic toxicity 2, 4

Evidence Quality Note

The most recent high-quality guideline from 2022 1 reinforces the 2008 recommendations 3 while updating the regional technique preference from femoral nerve block to adductor canal block, which preserves quadriceps strength better while providing equivalent analgesia. The addition of periarticular local infiltration analgesia represents an evolution in the evidence base since the earlier guidelines 1.