What is the anesthesia protocol for a knee replacement in a pediatric patient?

Anesthesia for Pediatric Knee Replacement

For pediatric knee replacement surgery, general anesthesia combined with ultrasound-guided femoral nerve block or fascia iliaca compartment block using long-acting local anesthetic with clonidine as adjunct, supplemented by multimodal analgesia with IV NSAIDs and acetaminophen, represents the optimal approach to minimize opioid requirements and optimize postoperative recovery. 1, 2

Primary Anesthetic Technique

General Anesthesia

• Total intravenous anesthesia (TIVA) with propofol and remifentanil is the preferred general anesthetic technique for pediatric orthopedic procedures, particularly in children with special needs 2
• Avoid preoperative sedation when possible to prevent behavioral escalation in anxious or autistic children 2

Regional Anesthesia Options

The regional component should include one of the following ultrasound-guided techniques:

• Femoral nerve block using 0.2-0.4 mL/kg of long-acting local anesthetic (bupivacaine or ropivacaine) combined with clonidine as adjunct 1, 3
• Fascia iliaca compartment block as an alternative that provides broader coverage of the surgical field 1
• Continuous peripheral nerve blocks are preferred over single-shot techniques for extended postoperative analgesia in major knee procedures 1, 4

The evidence strongly supports regional anesthesia in pediatric knee surgery, with studies demonstrating significantly lower pain scores (4.0 vs 5.3 on 0-10 scale), reduced opioid requirements (61% vs 71% needing opioids), shorter hospital stays (11.7 vs 15.8 hours), and lower admission rates (72% vs 95% for ACL repairs) compared to general anesthesia alone 3

Multimodal Analgesia Protocol

Baseline Non-Opioid Therapy

Administer the following medications preoperatively or intraoperatively and continue throughout the postoperative period:

• IV ketorolac 0.5-1 mg/kg (or alternative NSAID if ketorolac contraindicated) 1, 2
• IV acetaminophen in age-appropriate dosing 1, 2
• The combination of NSAID plus acetaminophen reduces opioid consumption and provides superior analgesia compared to either agent alone 1, 2

Adjunctive Medications

• IV dexamethasone to prolong block duration, reduce postoperative nausea/vomiting, and decrease supplemental analgesic requirements 1, 4
• Intraoperative low-dose ketamine as co-analgesic for opioid-sparing effect 1, 4
• Alpha-2 agonists (clonidine) added to regional blocks for extended analgesia 1, 4

Rescue Analgesia

• IV metamizole should be first-line rescue analgesic where available 1
• IV fentanyl reserved for breakthrough pain only in PACU 1, 2
• Oral/rectal/IV tramadol for moderate pain on the ward 1
• Avoid codeine per FDA guidelines due to respiratory risks in pediatric patients 2

Postoperative Care Strategy

PACU Management

• Standard monitoring with pulse oximetry 2
• IV fentanyl or other suitable opioid available for breakthrough pain 1
• Transition to oral medications as soon as feasible 1

Ward Management

• Continue scheduled NSAIDs and acetaminophen (oral, rectal, or IV routes) 1
• Tramadol or nalbuphine as rescue for moderate pain 1
• Extended monitoring if opioids required, particularly in younger children 2
• Regular pain assessments using age-appropriate scales 4

Implementation by Resource Level

Basic Level (Limited Resources)

• General anesthesia with IV fentanyl in divided doses 1
• Local wound infiltration by surgeon with long-acting local anesthetic 1
• Rectal NSAID and paracetamol 1

Intermediate Level (Standard Resources)

• General anesthesia plus landmark-based femoral nerve block 1
• Rectal or IV NSAID and paracetamol 1
• IV opioids only if regional anesthesia contraindicated 1

Advanced Level (Full Resources)

• TIVA plus ultrasound-guided continuous femoral or fascia iliaca block with clonidine adjunct 1, 2
• IV NSAID and acetaminophen 1, 2
• Multimodal adjuncts (ketamine, dexamethasone, alpha-2 agonists) 1, 4
• Patient-controlled analgesia (PCA) with appropriate monitoring for older children 1

Critical Safety Considerations

Regional Anesthesia Safety

• Perform all regional blocks after induction of general anesthesia in pediatric patients to ensure cooperation and comfort 5
• Use ultrasound guidance whenever available for improved safety and efficacy 1, 4, 3
• Keep local anesthetic concentrations low to minimize toxicity risk while maintaining efficacy 4
• Monitor for compartment syndrome, though evidence suggests regional anesthesia does not mask early signs when appropriate monitoring protocols followed 5

Opioid-Related Precautions

• Minimize systemic opioid use to reduce respiratory depression, nausea, vomiting, and delayed mobilization 2, 6
• Extended monitoring required if opioids administered, particularly in children under 3 years 2
• Avoid codeine and tramadol in very young children per FDA warnings 2

Common Pitfalls to Avoid

• Overreliance on opioids alone leads to increased side effects and delayed recovery; always use multimodal approach 2, 6
• Delaying regional block placement until after surgery misses opportunity for intraoperative analgesia and reduced anesthetic requirements 4, 5
• Single-shot blocks for major procedures when continuous catheters would provide superior extended analgesia 1, 4
• Inadequate baseline non-opioid therapy results in preventable breakthrough pain and increased opioid consumption 1, 2
• Failure to continue scheduled NSAIDs and acetaminophen after block resolution leads to rebound pain 4