What combined peripheral nerve block (PNB) technique and medication regimen should be used for an older adult undergoing revision total hip arthroplasty (THA) with comorbid cardiovascular disease, diabetes, and chronic pain?

Peripheral Nerve Block Strategy for Revision Total Hip Arthroplasty

Primary Recommendation

For revision THA in an older adult with cardiovascular disease, diabetes, and chronic pain, use a continuous posterior lumbar plexus (psoas compartment) block combined with a single-shot sciatic nerve block, supplemented with multimodal systemic analgesia including paracetamol and NSAIDs/COX-2 inhibitors (if not contraindicated by cardiovascular disease), plus IV PCA with strong opioids for breakthrough pain. 1

Rationale for Block Selection

Posterior Lumbar Plexus Block as Primary Technique

• Posterior lumbar plexus blocks provide superior analgesic efficacy compared to femoral nerve blocks for hip arthroplasty, with greater proximal spread and extended duration of analgesia 1
• Research demonstrates that lumbar plexus blocks reduce intraoperative opioid requirements by more than threefold and postoperative pain scores by fourfold compared to systemic analgesia alone 2
• Continuous infusion via catheter is recommended over single-shot to provide extended analgesia throughout the high-pain period following revision surgery 1
• Use 0.2% ropivacaine at 8 mL/hr for continuous infusion, or 20-30 mL of 0.25% bupivacaine/levobupivacaine for single-shot 3

Critical Safety Consideration for High-Risk Patient

However, posterior lumbar plexus blocks carry increased risk of serious complications including epidural spread, deep hematoma formation, and systemic toxicity 1, 3, 4

• This is particularly concerning in patients with cardiovascular disease who may require perioperative anticoagulation 5
• Epidural-like distribution occurs in approximately 10% of cases 2
• The risk-benefit balance must be carefully assessed for this individual patient 1

Alternative: Fascia Iliaca Block for Higher-Risk Patients

If the posterior lumbar plexus block is deemed too high-risk given cardiovascular comorbidities and potential anticoagulation needs:

• Fascia iliaca block is the preferred alternative, demonstrating lower pain scores, reduced morphine consumption, and shorter hospital stays without increased fall risk 4, 6
• Use supra-inguinal FICB technique with 20-40 mL of 0.25% bupivacaine with epinephrine 1:200,000 4
• Fascia iliaca blocks avoid the deep placement and epidural spread risk of lumbar plexus blocks while providing comprehensive hip coverage 4

Sciatic Nerve Block as Essential Adjunct

• Add a single-shot sciatic nerve block to address posterior hip innervation, which is critical for revision surgery involving posterior approach 7, 8, 9
• Combined lumbar plexus and sciatic blocks provide complete hip anesthesia and have been successfully used for primary THA 7, 9
• Use 20-30 mL of 0.25-0.5% bupivacaine or 0.2% ropivacaine 3

Why NOT Femoral Nerve Block Alone

• Femoral nerve blocks are inferior to lumbar plexus blocks for hip surgery, providing inadequate coverage of obturator and posterior hip structures 1
• Femoral blocks cause significant quadriceps weakness, increasing fall risk and delaying mobilization 3, 4, 6
• While femoral blocks are equivalent to lumbar plexus blocks for pain scores, they result in significantly reduced early ambulation (median 2m vs 11m on postoperative day 1) 5

Multimodal Systemic Analgesia Framework

Baseline Non-Opioid Regimen

Peripheral nerve blocks must never be used as monotherapy; always combine with systemic multimodal analgesia 1, 3

• Paracetamol (acetaminophen) is mandatory as baseline treatment for all pain intensities, as it decreases supplementary analgesic requirements 1
• Paracetamol should only be used in combination with other analgesics, never as sole agent 1

NSAIDs/COX-2 Inhibitors: Critical Caveat for Cardiovascular Disease

• COX-2 selective inhibitors or conventional NSAIDs are recommended for opioid-sparing effects 1
• HOWEVER, exercise extreme caution in patients with cardiovascular disease: COX-2 inhibitors and some NSAIDs increase cardiovascular risk 1
• If cardiovascular disease contraindicates NSAIDs/COX-2 inhibitors, rely more heavily on regional anesthesia and accept higher opioid requirements 1

Opioid Management Strategy

For high-intensity pain (VAS >50/100):

• IV patient-controlled analgesia (PCA) with strong opioids is recommended over fixed-interval or intramuscular administration 1
• Intraoperative administration of strong opioids is recommended to ensure analgesia upon emergence 1
• Intramuscular administration is NOT recommended due to injection-associated pain 1

For moderate-to-low intensity pain (VAS <50/100):

• Weak opioids are NOT recommended for high-intensity pain in the early postoperative period (<6 hours) 1
• Weak opioids combined with paracetamol are appropriate later when pain intensity decreases 1

Special Considerations for Chronic Pain Patient

• Patients with chronic pain typically have opioid tolerance and require higher analgesic doses 1
• The superior analgesia from lumbar plexus block is particularly valuable in this population to minimize opioid escalation 2
• Consider preoperative pain medicine consultation for optimization of chronic pain regimen perioperatively

Anesthetic Technique Consideration

• Neuraxial anesthesia (spinal or epidural) is preferred over general anesthesia for the primary anesthetic, as it reduces perioperative complications in hip arthroplasty 1
• For patients with cardiovascular disease, continuous epidural analgesia with local anesthetic and opioids is specifically recommended due to decreased cardiopulmonary morbidity 1
• However, epidural requires relatively high patient monitoring compared to peripheral blocks 1
• If general anesthesia is used, the peripheral nerve blocks become even more critical for postoperative analgesia 1

Common Pitfalls to Avoid

• Do not use epidural clonidine despite analgesic efficacy, due to risk of hypotension, sedation, and bradycardia in cardiovascular disease patients 1
• Do not use spinal clonidine, as it is less effective than spinal morphine 1
• Avoid continuous spinal infusion despite analgesic efficacy, due to increased complication potential 1
• Do not rely on intra-articular local anesthetic alone, as evidence is inconsistent for hip surgery 1
• Ensure fall precautions if using lumbar plexus or femoral blocks due to motor blockade 3, 4, 6