The analgesic effect of continuous adductor canal block combined with popliteal plexus block for total knee arthroplasty: a randomized controlled trial

Abstract This study aimed to confirm the hypothesis that continuous ACB (CACB) combined with a popliteal plexus block (PPB) can improve posterior knee pain, reduce nalbuphine consumption, and shorten the length of hospital stay. Patients who underwent TKA were allocated to the CACB + sham block (SHAM) or CACB + PPB groups. The primary outcome was the maximum pain score originating from the posterior knee within 4 h after TKA. Secondary outcomes included the maximum pain score originating from the posterior and anterior knees within 72 h after TKA, range of motion on postoperative day (POD) 1–3, postoperative nalbuphine consumption within 72 h of surgery, length of hospital stay, and complications. The maximum pain score of the posterior knee was lower in the CACB + PPB group than in the CACB + SHAM group within 0–12 h after surgery. Nalbuphine consumption within 24 h after surgery was lower in the CACB + PPB group than in the CACB + SHAM group. The range of motion was better in the CACB + PPB group than in the CACB + SHAM group on POD1 and 2. The length of hospital stay was shorter in the CACB + PPB group than in the CACB + SHAM group. The incidence of clinical significant nausea and vomiting was lower in the CACB + PPB group than in the CACB + SHAM group. This study found that PPB combined with CACB could relieve pain in the posterior knee within at least 12 h after TKA, reduce nalbuphine consumption within 24 h after TKA, improve the range of motion on POD1 and 2, and shorten the length of hospital stay for patients who underwent TKA.