Efficacy, Safety, and Pharmacokinetics of Femoral Nerve Block With EXPAREL in Total Knee Arthroplasty

On Day 0, eligible subjects will be randomized in a 1:1:1 ratio to receive a single dose of either EXPAREL 133 mg in 10 mL expanded in volume with 10 mL of normal saline for a total volume of 20 mL (Group 1); EXPAREL 266 mg in 20 mL (Group 2); or placebo 20 mL (Group 3). Study drug (EXPAREL or placebo) will be administered in a blinded manner via an ultrasound guided single-dose femoral nerve block at least 1 hour prior to surgery. Prior to placement of the prosthesis, 8 mL of bupivacaine hydrochloride (HCl) (0.5%) diluted with 8 mL of normal saline will be administered by the surgeon as a periarticular infiltration to the posterior capsule (8 mL medially and 8 mL laterally). Postsurgical assessments will include pain intensity scores using a 10-cm visual analog scale (VAS); total postsurgical opioid consumption; overall benefit of analgesia score (OBAS) questionnaire; subject satisfaction with overall analgesia using a 5-point Likert scale; neurological assessment; sensory function assessment; motor function assessment; the study physical therapy assessments (ie, timed walk, timed up and go, and stair climbing tests); discharge readiness; unscheduled phone calls or office visits related to pain; 12-lead ECGs; vital sign measurements; and clinical laboratory tests. Adverse events will be recorded from the time the informed consent form (ICF) is signed through postsurgical Day 29. Follow-up visits will be scheduled for all subjects on postsurgical Days 6 and 10. A follow-up phone call will be made on postsurgical Day 29. Pharmacokinetic (PK) parameters will be estimated from plasma bupivacaine measurements using non-compartmental analysis based on the sampling schedule of baseline (prior to the nerve block) through postsurgical Day 10.