Postoperative pain after joint replacement surgery : A randomized controlled trial of transcutaneous auricular vagus nerve stimulation and the role of depression and anxiety.

Study Summary

44 patients undergoing elective hip, knee, shoulder, or ankle joint replacement were randomized to receive transcutaneous auricular vagus nerve stimulation (taVNS), sham stimulation, or treatment as usual (TAU). taVNS and sham stimulation were administered 2–3 times daily for 40–60 minutes over 3–5 days, while TAU consisted of standard postoperative analgesia and physiotherapy. The primary outcome of interest was postoperative pain measured using the Short-Form McGill Pain Questionnaire (SF-MPQ). Secondary outcomes included depressive symptoms measured using the Patient Health Questionnaire-9 (PHQ-9), anxiety measured using the Generalized Anxiety Disorder-7 (GAD-7), and moderation of pain changes by depressive and anxiety symptoms. Outcomes were assessed at hospital admission and before discharge. Overall, the results of the study revealed no significant differences in postoperative pain between groups or over time, and neither depressive nor anxiety symptoms moderated the treatment effect. These findings suggested that short-term postoperative taVNS did not provide an additional analgesic benefit over sham stimulation or standard care.