Capsaicin instillation for postoperative pain following total knee arthroplasty: a preliminary report of a randomized, double-blind, parallel-group, placebo-controlled, multicentre trial

16 patients were randomized to examine whether direct instillation of a capsaicin preparation into the wound after total knee arthroplasty (TKA) would improve clinical outcomes. Patients received either 5 mg capsaicin, or 15 mg capsaicin, or a placebo and were assessed after the first 24 hours and then daily for 3 days. Results revealed that the capsaicin groups produced comparable or better pain scores with significantly less opioid use when compared to the placebo group.