Is it safe to mix lidocaine (local anesthetic) and Kenalog (triamcinolone) in the same syringe for a lateral access knee injection?

Mixing Lidocaine and Kenalog for Lateral Access Knee Injection

Yes, lidocaine and Kenalog (triamcinolone acetonide) can be safely mixed in the same syringe for lateral access knee injection, as supported by current guidelines and clinical practice. 1

Rationale for Combining Agents

• Pain management: Lidocaine provides immediate anesthesia during the procedure, reducing patient discomfort
• Therapeutic effect: Triamcinolone (Kenalog) provides longer-term anti-inflammatory benefits
• Standard practice: Mixing local anesthetics with corticosteroids is a common and recommended approach for intra-articular injections

Proper Mixing Technique

1. Use aseptic technique throughout the procedure 1
2. Draw up medications in the following order:
   • First: 1-2 mL of 1% lidocaine
   • Second: Triamcinolone acetonide (typically 40 mg/1 mL)
3. No need to change needles between drawing medications and injecting the mixture

Dosing Considerations

• Standard mixture: 2 mL of 1% lidocaine with 40 mg (2 mL) of triamcinolone acetonide is a common formulation 2
• Maximum safe dose: Do not exceed 7 mg/kg of lidocaine with epinephrine or 4.5 mg/kg without epinephrine 3
• Considerations for specific populations:
  • Patients with diabetes: Monitor for transient hyperglycemia for 1-3 days post-injection 1
  • Patients with prosthetic joints: Consult with orthopedic team before injection 1

Clinical Benefits of Combined Injection

• Reduced procedural pain: Local anesthetic component minimizes discomfort during injection 1
• Extended pain relief: The combination provides both immediate and sustained relief 4
• Improved patient experience: Patients report better satisfaction with combined injections 4
• Earlier return to activity: Combined treatment may allow quicker return to daily activities 4

Potential Adverse Effects

• Post-injection flare: Some patients may experience a transient increase in pain and swelling within hours of injection, which can mimic septic arthritis but typically resolves within 1-2 days 2
• Crystal-induced inflammation: Triamcinolone crystals can occasionally trigger an acute inflammatory response 2
• Tenocyte effects: In vitro studies suggest lidocaine may potentiate triamcinolone's effects on tenocytes, so caution is advised when injecting near tendons 5

Important Precautions

• Avoid in active infection: Do not inject if there is suspicion of joint infection
• Timing considerations: If joint replacement surgery is planned, injection should be performed at least 3 months prior 1
• Diabetic monitoring: Advise diabetic patients to monitor glucose levels for 1-3 days post-injection 1

Common Pitfalls to Avoid

• Inadequate aseptic technique: Always maintain strict sterility to prevent infection
• Improper needle placement: Ensure accurate intra-articular placement, consider ultrasound guidance if available 1
• Excessive dosing: Using too much corticosteroid or lidocaine can increase risk of adverse effects
• Failure to aspirate: Always aspirate before injection to confirm proper needle placement and check for effusion

By following these guidelines, the combined injection of lidocaine and Kenalog provides an effective approach for managing knee pain while minimizing patient discomfort during the procedure.