Adductor Canal Catheter Effectiveness and Safety Study

PRIMARY OBJECTIVE: Compare the effect of usual care with an adductor canal catheter (ACC) containing ropivacaine to the effect of usual care without an ACC on the second-postoperative-day pain levels among patients undergoing elective primary unilateral total knee arthroplasty (TKA) SECONDARY OBJECTIVES: Among a sample of patients undergoing elective primary unilateral TKA who receive peri-articular anesthetic injections: 1. To compare the overall two-week levels of postoperative pain between those participants randomized to ACCs containing ropivacaine and those participants randomized to usual care without an ACC 2. To compare the use of opioid medications (in mean total morphine milligram equivalents) between those participants randomized to ACCs containing ropivacaine and those participants randomized to usual care without an ACC over the two-week postoperative period 3. To describe the incidence of complications related to ACC placement including infection, displacement, ACC-related clinic or emergency department (ED) visits 4. To conduct exploratory analyses to identify candidate predictors of differential response to the ACC