Why 1% Lidocaine is Preferred Over 2% for Joint Injections
For joint injections, 1% lidocaine is preferred over 2% lidocaine because it provides adequate anesthesia with a lower risk of chondrotoxicity while maintaining the same clinical efficacy.
Rationale for Using 1% Lidocaine
Safety Profile
- Research shows that local anesthetics can be toxic to chondrocytes (cartilage cells), with higher concentrations causing greater damage 1
- 1% lidocaine demonstrates less chondrotoxicity compared to 2% lidocaine while still providing effective anesthesia 1
- The American College of Rheumatology guidelines recommend using the lowest effective concentration of local anesthetic for joint injections 2
Clinical Efficacy
- 1% lidocaine provides sufficient analgesia for joint injections as demonstrated in clinical practice 3
- According to the 2025 American Journal of Obstetrics and Gynecology guidelines, "the more commonly available 1% lidocaine and a regular syringe can be used" as an alternative to 2% lidocaine for procedures requiring local anesthesia 3
- When buffered, 1% lidocaine has been shown to be equally effective to other local anesthetics for pain control during procedures 4
Practical Considerations
- Lower concentration allows for greater volume of injection when needed, which can be beneficial for larger joints 2
- 1% lidocaine is more commonly available in clinical settings 3
- For intracervical blocks, studies have shown that buffered 20 mL of 1% lidocaine is effective for pain reduction during procedures 3
Dosing Considerations
Recommended Volumes
- For knee, hip, and shoulder injections, sports medicine physicians typically use 5-7 mL total injectate volume (including corticosteroid and lidocaine) 5
- For smaller joints or bursae, 3-4 mL total volume is more common 5
Safety Limits
- Maximum safe dose of lidocaine should not exceed 7 mg/kg when used with epinephrine 2
- For a typical joint injection, 2-4 mL of 1% lidocaine (20-40 mg) stays well below toxic thresholds 2
Special Considerations
Patient-Specific Factors
- Extra caution is needed when using lidocaine in:
- Patients over 70 years of age
- Those with heart failure or hepatic dysfunction
- Patients with severe renal dysfunction 2
Technique Recommendations
- Image guidance (particularly ultrasound or fluoroscopy) is strongly recommended for deep joint injections to ensure accurate placement 3, 2
- Aspiration of synovial fluid before injection helps confirm proper needle placement 3
- Aseptic technique is essential for all joint injections 3
Alternatives to Consider
- Bacteriostatic saline (0.9% benzyl alcohol in normal saline) has been shown to be equally effective to buffered 1% lidocaine for local anesthesia before ultrasound-guided hip joint injections 4
- Ropivacaine may be considered for patients with higher risk of chondrotoxicity as it appears to have the lowest toxic potential on human chondrocytes 1
By using 1% lidocaine instead of 2% for joint injections, clinicians can achieve adequate anesthesia while minimizing potential risks to cartilage health and maintaining the same clinical efficacy.