Topical Anesthesia for Removal of Stitches After Total Knee Arthroplasty

Inclusion criteria: 1. Males and females, aged 50-100 years 2. The patients who undergo primary total knee replacement (performed by the same surgeon, Dr.Jiang) 3. Clear consciousness 4. No contraindication for staple removal on the post-operative day 7 Exclusion criteria: 1. Allergy to lidocaine 2. Patient with second or third degree atrio-ventricular block 3. Patients with severe Sinoatrial node block 4. Patients taking class I antiarrhythmia drugs 5. Pregnant patients 6. Patients undergoing revision total knee replacement 7. Contraindication for removal of staples on post-operative day 7