The Effects of Perineural Dexamethasone on Rebound Pain After Nerve Block in Patients with Unicompartmental Knee Arthroplasty A Randomized Controlled Trial

Abstract

Objectives: A single nerve block provides excellent analgesia in a short time, but rebound pain after the nerve block disappears has attracted researchers’ attention. The aim of this study is to evaluate the effect of perineural dexamethasone on rebound pain after sciatic nerve block and femoral nerve block in patients undergoing unicompartmental knee arthroplasty (UKA). Methods: In a double-blinded fashion, We recruited 72 patients undergoing UKA, each of whom received sciatic and femoral nerve block. Patients were randomly assigned to two groups (n=36): X (ropivacaine only) and D (ropivacaine combined with dexamethasone). The primary outcome was the incidence of rebound pain. The secondary outcomes were rebound pain score, the duration of rebound pain, the duration of nerve block, pain score, sufentanil consumption and rescue analgesic, patient-controlled intravenous analgesia, distance walked, sleep quality score, C-reactive protein levels, and adverse effects. Results: Compared with group X, the incidence of rebound pain in group D was higher, the rebound pain score was higher and the duration of nerve block was prolonged (P<0.05). At 12, 16, and 20 hours postoperatively, the pain scores at rest in group D was lower. At 32 and 36 hours postoperatively, the pain scores at rest in group D was higher (P<0.05). Moreover, patients in group D had lower levels of C-reactive protein after surgery (P<0.05). Discussion: Addition of dexmedetomidine to ropivacaine for UKA effectively prolonged the duration of nerve block and decreased c-reactive protein levels, but increased the incidence of rebound pain and rebound pain score, and had no beneficial effects on the postoperative analgesia.