Continuous adductor canal block added to local infiltration analgesia (LIA) after total knee arthroplasty has no additional benefits on pain and ambulation on postoperative day 1 and 2 compared with LIA alone

Background and purpose — The additional effects of a continuous adductor canal block (ACB) compared with a single-dose local infiltration anesthesia (LIA) after total knee arthroplasty (TKA) has not been widely researched. Both methods have good effect individually. We hypothesized that a continuous ACB added to a single-dose LIA would lower pain scores while ambulating on postoperative day 1 (POD1) and postoperative day 2 (POD2).

Patients and methods — 69 participants were included in this prospective, randomized, double-blind, placebo-controlled trial. The TKA was performed under spinal analgesia and every participant was given single-dose LIA intraoperatively. Patients were then randomized into 2 groups, treatment group receiving 0.2% ropivacaine and control group receiving normal saline. First a 20 mL bolus was given into the adductor canal and 4 hours later a continuous flow at 6 mL/h was initiated for 2 postoperative days through a catheter placed in the adductor canal.

Results — Worst pain score during movement of the operated knee on POD1 and POD2 was similar between the groups. No other ambulation tests done on POD1 and POD2 showed any statistically significant difference. Morphine consumption on the day of surgery, POD1 and POD2 was similar between the groups.

Interpretation — The results indicate no benefit of continuous infusion ACB added to a single-dose LIA compared with LIA alone on pain while ambulating on POD1 and POD2. Furthermore, the ACB showed no superiority in ambulation ability on the 2 postoperative days.