Total Knee Arthroplasty Infiltration Study for Postoperative Analgesia

Inclusion Criteria: * Is scheduled to undergo primary unilateral TKA under general anesthesia. * Has not previously undergone TKA in either knee. * Has an American Society of Anesthesiologists Physical Status of I, II, or III. * Is able to demonstrate motor function by performing a timed 20-meter walk unassisted, but with the optional use of a 4-legged walker for balance. * Female subjects are eligible only if not pregnant, not lactating, not planning to become pregnant during the study, sterile; or using acceptable contraceptives. Exclusion Criteria: * Has a planned concurrent surgical procedure (eg, bilateral TKA). * Has a pre-existing concurrent acute or chronic painful/restrictive physical condition that may require analgesic treatment in the postoperative period for pain. * Has a contraindication or a known or suspected history of hypersensitivity or idiosyncratic reaction to required study medications. * Has known or suspected daily use of opioids for 7 or more consecutive days within the previous 6 months. * Has taken NSAIDs within 10 days prior to the scheduled surgery. * Has taken opioids within 24 hours prior to the scheduled surgery (3 days for long-acting). * Has been administered bupivacaine within 5 days prior to the scheduled surgery. * Has initiated treatment with medications within 1 month prior to study drug administration that can impact pain control. * Has been administered systemic steroids within 5 half-lives or 10 days prior to administration of study drug. * Has a medical condition such that, in the opinion of the Investigator, participating in the study would pose a health risk to the subject or confound the postoperative assessments. * Has a known history of Hepatitis B, human immunodeficiency virus (HIV), or active Hepatitis C. * Has uncontrolled anxiety, psychiatric, or neurological disorder that might interfere with study assessments. * Has any chronic neuromuscular deficit of either femoral nerve function or thigh musculature. Has any chronic condition or disease that would compromise neurological or vascular assessments. * Had a malignancy in the last year, with the exception of non-metastatic basal cell or squamous cell carcinoma of the skin or localized carcinoma in situ of the cervix. * Has a known or suspected history of drug abuse, a positive drug screen on the day of surgery, or a recent history of alcohol abuse. * Received an investigational product or device in a clinical trial within 30 days or within 5 elimination half lives. * Has undergone 3 or more surgeries within 12 months. * Has a body mass index (BMI) \>38 kg/m2.