Efficacy of Single Injection Femoral Nerve Block With Liposomal Bupivacaine for Total Knee Arthroplasty

Inclusion Criteria: 1. Male or female, ≥18 years of age 2. Scheduled to undergo primary unilateral TKA under general anesthesia. 3. American Society of Anesthesiology (ASA) Physical Status I-III 4. Able to demonstrate motor function by performing a 20-meter walk, and sensory function by exhibiting sensitivity to cold. 5. Able to provide informed consent, adhere to the study visit schedule, and complete all study assessments. Exclusion Criteria: 1. Currently pregnant, nursing, or planning to become pregnant during the study or within 1 month after study drug administration. 2. Planned concurrent surgical procedure (e.g., bilateral TKA). 3. Body weight \< 50 kg (110 pounds) or a body mass index ≥ 40 kg/m2. 4. Contraindication to any of the pain-control agents planned for postsurgical use (i.e., morphine, hydromorphone, oxycodone, bupivacaine). 5. Previous participation in a liposome bupivacaine study. 6. History of, suspected, or known addiction to or abuse of illicit drug(s), prescription medicine(s), or alcohol within the past 2 years. 7. Uncontrolled anxiety, schizophrenia, or other psychiatric disorder that, in the opinion of the investigator, could interfere with study assessments or compliance.