Effectiveness of Exparel Anesthetic Administered by the Surgeon During Knee Surgery

Intra-articular Posteromedial Surgeon Administered (IPSA) Block in this study describes a new type of medical procedure where a surgeon provides anesthetic medication directly into a specific area inside a knee joint to numb the pain during knee surgery. Intra-articular refers to inside of knee joint, posteromedial refers to the back and inner side of a knee joint, and surgeon administered means a surgeon is performing the procedure. Patients You will be randomly assigned to one of these three treatment groups: Group 1: Patients in this group will receive IPSA block and Local Infiltration Analgesia (LIA). IPSA block is a pain numbing medication given by surgeon and injected inside the back and inner side of the knee joint. Local Infiltration Analgesia is a pain numbing medication injection given by the surgeon around the surgical knee area. The medications used in the procedure will be EXPAREL, and Bupivacaine HCL. Group 2 (Control): Patients in this group will receive Adductor Canal Block (ACB) and Local Infiltration Analgesia (LIA). ACB is a pain numbing injection given by anesthesiologist near the adductor canal, a passage in the mid-thigh that contains nerves connecting the knee region. Local Infiltration Analgesia is a pain numbing medication injection given by the surgeon around the surgical knee area. The medications used in the procedure will be EXPAREL, and Bupivacaine HCL. Group 3: Patients in this group will receive Local Infiltration Analgesia (LIA). Local Infiltration Analgesia is a pain numbing medication injection given by the surgeon around the surgical knee area. The medications used in the procedure will be EXPAREL, and Bupivacaine HCL. The study will evaluate; * How effective the pain relief is after surgery. * How much extra pain medication you need. * Your satisfaction with pain management and recovery * Any side effects.

Inclusion Criteria: Inclusion Criteria: Subjects must meet all of the following inclusion criteria to be eligible for participation: 1\. Subjects ages 18 or older at screening 2. Indicated to undergo primary unilateral total knee arthroplasty under spinal anesthesia 3. Primary indication for TKA is degenerative osteoarthritis of the knee 4. American Society of Anesthesiologists (ASA) physical status 1, 2, or 3 (see Appendix 6) 5. Able to provide informed consent, adhere to the study schedule, and complete all study assessments 6. Body Mass Index (BMI) ≥18 and \