Topical anesthesia for staple removal from surgical wounds on the knee: a prospective, double-blind, randomized trial.

BACKGROUND: Staple removal from surgical wounds is painful. Only a few articles have provided expert opinions using anesthetic cream for such a problem; however, direct application of the anesthetic cream to a wound may cause infection. A safe alternative can be an anesthetic patch without wound contact. MATERIALS AND METHODS: This was a prospective, double-blind, randomized clinical trial. Sixty patients who underwent primary total knee replacement were assigned to an experimental group or control group. One lidocaine patch was applied around the surgical wound for each patient in the experimental group. Alternatively, the adhesive sides of the lidocaine patches were shielded with waterproof films in the control group. A resident peeled off the patch before a single nursing practitioner removed the staples. Pain was assessed with the 10-cm visual analog scale, and a face pain scale-revised was performed. The patients and the nursing practitioner were blind to the management. RESULTS: Mean visual analog scale and face pain scale-revised scores were significantly lower in the experimental group. The mean pain score was significantly lower in the experimental group if the application time was >47 min; for patients with application time of 47 min or shorter, the score was comparable with the mean pain scores of the control group (P = 0.215). CONCLUSIONS: Removal of the metal skin staples after total knee arthroplasty is associated with moderate-to-severe pain. The lidocaine patch applied topically around the surgical wound could effectively reduce the pain during the procedure, without remarkable complications such as systemic adverse effects or wound contamination.