Lidocaine local anesthesia for arthroscopic knee surgery

Area of Science:

• Anesthesiology
• Orthopedic Surgery

Background:

• Intraarticular lidocaine with epinephrine is used for local anesthesia during knee arthroscopy.
• Determining the optimal dose-response relationship for operative analgesia is crucial for patient comfort and procedural success.

Purpose of the Study:

• To evaluate the dose-response relationship of intraarticular lidocaine with epinephrine for analgesia during knee arthroscopy.
• To compare patient-reported pain scores and willingness to repeat the anesthetic technique across different lidocaine concentrations.

Main Methods:

• Forty-five patients undergoing knee arthroscopy were prospectively randomized to receive 20 mL of 0.5%, 1.0%, or 1.5% lidocaine with epinephrine intraarticularly.
• Intraoperative discomfort was assessed using an 11-point linear pain scale.
• Serum lidocaine concentrations were monitored at various time points.

Main Results:

• Pain scores were significantly higher in the 0.5% lidocaine group during the initial 45 minutes of surgery (P=0.03).
• While pain scores remained higher in the 0.5% group post-45 minutes, the difference was not statistically significant.
• Patient willingness to repeat the anesthetic technique was highest in the 1.5% lidocaine group (94%).
• No patient experienced symptoms of lidocaine toxicity, with peak serum concentrations observed in the 1.5% group.

Conclusions:

• Intraarticular lidocaine concentrations of 1.0% or 1.5% are recommended for knee arthroscopy when using 20 mL, offering improved patient comfort.
• These higher concentrations provide effective operative analgesia without adverse effects or toxicity.
• The study supports the use of 1.0% or 1.5% lidocaine for intraarticular anesthesia in knee arthroscopy based on patient-reported outcomes and safety profile.