Adductor Canal Block Versus Periarticular Bupivicaine Injection in Total Knee Arthroplasty

Over 600,000 total knee arthroplasties (TKAs) are performed each year in the United States, with expectations for greater than 4 million/year by the year 2030. Since the onset of TKAs in the 1960's, there have been developments that have improved both functionality and patient satisfaction. In the last decade, a focus has been made on multimodal pain management protocols, more rapid functional recovery, reduced length of hospital stay, and minimizing side effects of treatment while maintaining function and durability. The widespread use of regional anesthesia has led to improvements in pain control, more rapid functional recovery, and reduced length of stay. In recent years many surgeons have transitioned from femoral nerve blocks (proximal femoral nerve) to adductor canal blocks (distal femoral nerve) to maintain a sensory block for pain control, while minimizing any motor blockade that is typically seen in proximal femoral nerve blocks, which would hamper rehabilitation, and increase risk of falls. In addition to regional blocks, which are typically performed in the preoperative setting, some surgeons favor an intraoperative periarticular anesthetic injection (PAI), typically with bupivacaine or the long acting form liposomal bupivacaine, either in conjunction with an adductor canal block, or independently. In theory, PAI has the advantage of a comparable sensory nerve block as an adductor canal block, without the disadvantages and risks, which include prolonged quadriceps weakness, fall risk, and neurologic dysfunction. The purpose of this randomized control trial is to compare the efficacy of adductor canal blocks versus periarticular bupivacaine injections for pain management in total knee arthroplasty.