Comparison of Analgesic Efficacy of Continuous Adductor Canal Block versus Single-shot Adductor Canal Block Using Ropivacaine for Unilateral Total Knee Arthroplasty: A Randomized Controlled Trial

Total knee arthroplasty (TKA) associated with moderate-to-severe surgical site pain postoperatively requires multimodal analgesia for which adductor canal block (ACB) is an effective modality. The aim of this study was to compare the analgesic efficacy of continuous versus single-shot ACB in patients undergoing unilateral TKA. It was a prospective randomized controlled trial carried out in a tertiary care hospital. Sixty patients (18–65 years) undergoing unilateral TKA were prospectively randomized into continuous (CACB) and single (SACB) shot adductor canal blockade groups. Postoperative ultrasound-guided ACB was given, and the Visual Analog Scale (VAS) scores, time to first rescue analgesia, and total amount of analgesia required in 24 and 48 h were noted. Straight leg raise (SLR) test and maximum knee extension test were performed to check for quadriceps muscle strength. Both the groups were compared using appropriate statistical tests, with P < 0.05 considered statistically significant. In both the demographically comparable groups, VAS scores were similar at 0, 4, 8, and 12 h postsurgery, but higher in the SACB group at 24 (P < 0.0001) and 48 h (P = 0.02), needing rescue analgesia in 4 out of 30 patients. One out of 30 patients of the SACB group could not perform the SLR test on the 1st postoperative day. Knee extension was present in all 60 patients. ACB is a pure sensory block. CACB provides a longer duration of analgesia; however, SACB can be an equally useful alternative in resource-limited settings, to avoid catheter dislodgement, risk of infection, and need for continuous monitoring.