Genicular Nerve Block for Total Knee Arthroplasty

Part of the way in which pain is controlled during total knee replacement surgery is through a nerve block. The investigators have developed an effective protocol for pain control after knee replacement, but know that many patients still experience pain around the knee after knee replacement. There are nerves around the knee that carry pain impulses from behind the knee. The investigators believe that placing numbing medicine around these nerves can help with pain in front of the knee after surgery, in addition to the standard nerve block placed for knee replacement surgery. This may result in taking less pain medication by mouth,and having less pain with movement. For this study, before the operation, either a placebo solution or the local anesthetic bupivacaine (a numbing solution) will be placed at three sites around the knee where these nerves reside. The investigators will evaluate how participants feel in recovery after surgery, during the stay in the hospital, and call at home one week after surgery. Knowing if numbing these nerves helps with pain after surgery will help us further refine our postoperative care plan for patients.

Inclusion criteria

• Subjects scheduled for primary elective total knee arthroplasty
• American Society of Anesthesiologists Physical Status I-III
• BMI 18-40 kg/m2

Exclusion criteria

• Inability to cooperate with protocol
• Inability to understand or speak English
• Allergy to ropivacaine, bupivacaine or other local anesthetic
• Contraindication to peripheral nerve block (e.g. local infection, neurologic deficit or disorder, previous trauma or surgery to ipsilateral knee, etc.)
• Revision knee surgery
• Chronic opioid consumption (daily morphine equivalent of >30 mg for at least four weeks prior to surgery)
• History of chronic pain
• History of psychiatric disorder
• History of diabetes mellitus