What is the recommended approach for pain management using regional blocks in joint replacement surgeries?

Regional Blocks for Joint Replacement: Current Guidelines

For total hip arthroplasty, use a pericapsular nerve group (PENG) block combined with local infiltration analgesia (LIA), or alternatively a lumbar plexus block plus LIA, as these provide superior pain control with motor-sparing effects. 1

For total knee arthroplasty, use a single-shot adductor canal block or periarticular infiltration (PAI), or combine both for patients at high risk of poor pain control. 2

Total Hip Arthroplasty: Regional Block Recommendations

First-Line Options (Motor-Sparing)

• PENG block plus LIA ranks highest for dynamic pain control at 6 hours postoperatively and provides motor-sparing effects, making it the optimal choice for early mobilization 1
• Lumbar plexus block (LPB) plus LIA demonstrates superior static pain control at 12 hours and reduced opioid consumption at 24 hours, though carries higher complication risk than peripheral blocks 1, 3
• Quadratus lumborum block plus fascia iliaca compartment block (FICB) provides excellent opioid-sparing effects (highest SUCRA ranking at 85.5%) but may cause some motor blockade 1

Alternative Single-Shot Blocks

• Femoral nerve block provides excellent static pain control at 6 hours (SUCRA=92.8%) but causes significant quadriceps weakness, delaying mobilization 1, 3
• Fascia iliaca block offers comparable analgesia to femoral nerve block with potentially less motor blockade, though evidence shows higher pain scores than femoral block by 5mm 3
• Posterior lumbar plexus blocks (psoas compartment blocks) have greater efficacy than femoral blocks but carry increased risk of serious complications including epidural spread and should be reserved for select patients 3

Continuous vs. Single-Shot Techniques

• Continuous peripheral nerve blocks via catheter provide extended analgesia duration compared to single-shot approaches 3
• However, continuous techniques require higher monitoring intensity and may not justify the risk-benefit profile compared to single-shot blocks with multimodal analgesia 3

Total Knee Arthroplasty: Regional Block Recommendations

Preferred Approaches

• Single-shot adductor canal block provides effective pain reduction and opioid-sparing without quadriceps weakness, allowing earlier mobilization 2, 3
• Periarticular infiltration (PAI) alone demonstrates equivalent efficacy to adductor canal block for pain and opioid consumption 2
• Combination of adductor canal block plus PAI may provide superior analgesia for patients with anticipated severe postoperative pain 2

Avoid or Use With Caution

• Femoral nerve blocks are effective for analgesia but cause significant quadriceps weakness, increasing fall risk and delaying rehabilitation 2, 3
• Continuous adductor canal blocks may improve analgesia over single-shot but require additional monitoring and catheter management 2
• Epidural analgesia provides effective pain control but has less favorable risk-benefit profile, requiring intensive monitoring compared to peripheral blocks 3

Neuraxial Techniques

Spinal Analgesia

• Single-shot spinal with local anesthetic plus morphine (0.1-0.2 mg) provides superior postoperative analgesia compared to systemic, epidural, or lumbar plexus blocks 3
• Spinal morphine combined with local anesthetic demonstrates superior efficacy and duration compared to either agent alone 3
• Single bolus dosing is recommended over continuous spinal infusion due to increased complication potential with continuous techniques 3

Epidural Analgesia

• Continuous epidural with local anesthetic plus opioids is recommended specifically for cardiopulmonary risk patients due to decreased cardiopulmonary morbidity 3
• Despite efficacy, epidural provides less favorable risk-benefit profile than peripheral blocks and requires intensive monitoring 3
• Epidural clonidine is not recommended due to risks of hypotension, sedation, and bradycardia 3

Essential Multimodal Analgesia Components

Baseline Non-Opioid Regimen (All Patients)

• Paracetamol (acetaminophen) as baseline treatment for all pain intensities, decreasing supplementary analgesic requirements 3, 4
• NSAIDs or COX-2 selective inhibitors unless contraindicated, combined with paracetamol 3, 4
• Continue non-opioid regimen throughout postoperative period to prevent rebound pain after regional block resolution 4

Opioid Management

• Intravenous patient-controlled analgesia (PCA) or fixed-interval IV administration for high-intensity pain (VAS >50) 3
• Weak opioids (e.g., tramadol) only for moderate-to-low intensity pain (VAS <50) after 6 hours postoperatively, not for early high-intensity pain 3
• Intramuscular opioid administration is not recommended due to injection-associated pain 3

Critical Safety Considerations

Infection Risk

• Regional blocks should be performed at anatomical sites distant from any active infection to minimize spread risk 4, 5
• Proper aseptic technique is mandatory even in patients with systemic infections like Pseudomonas 5
• Ensure patients with active infections receive appropriate antibiotic therapy before block placement 5

Motor Blockade Concerns

• Femoral nerve blocks and FICB cause significant quadriceps and adductor weakness, increasing fall risk 1, 2
• LPB carries higher complication risk than peripheral blocks, including potential epidural spread 3, 1
• Motor-sparing blocks (PENG, adductor canal) should be prioritized to facilitate early mobilization 1, 2

Common Pitfalls to Avoid

• Do not rely on regional blocks alone - always combine with scheduled non-opioid multimodal analgesia to prevent rebound pain 4
• Avoid continuous epidural for routine cases - reserve for high cardiopulmonary risk patients only due to monitoring requirements 3
• Do not use spinal clonidine - less effective than spinal morphine and causes hypotension 3
• Avoid femoral blocks when early mobilization is critical - quadriceps weakness delays rehabilitation 1, 2