Pilot Study on EXPAREL as an Intra-articular Posteromedial Surgeon Administered (IPSA) Block vs. Local Infiltration Analgesia in Knee Replacement Surgery

The study aims to test the safety and effectiveness of two different surgeon-administered methods of the anesthesia medication EXPAREL during knee replacement surgery. This study will not determine whether one method is better than the other, but will instead help the study investigator decide if both methods can provide an equal amount of pain relief. The main question this study aims to answer is: Will EXPAREL provide an equal amount of pain relief for patients who receive EXPAREL via Intra-articular Posteromedial Surgeon Administered (IPSA) Block and patients that receive EXPAREL via Local Infiltration Analgesia (LIA)? Following their surgery, participants will be asked to report their pain level on their treated knee using a numerical rating scale (NRS) between 0 to 10. In addition to their pain level, participants will report any medications used for pain relief and will mark specific regions on an image to indicate where they experience pain.