Addition of Muscle Relaxants in a Multimodal Analgesic Regimen for Analgesia After Primary Total Knee Arthroplasty

Inclusion Criteria: * \- Patients undergoing unilateral primary TKA with underlying diagnosis of osteoarthritis. * ASA I - III * Spinal anesthesia * All patients will have a total knee arthroplasty utilizing a medial parapatellar approach with cruciate sacrificing implants and patellar resurfacing. A tourniquet will be used in all cases. * Men and women between 18 and 80 years who are willing and able to provide informed consent Exclusion Criteria: * Opioid use greater than 10 mg/day morphine equivalents continuously for one month within 3 months preoperatively * Inability to take/allergy to the protocol medications * Contraindication to regional anesthesia * Non-English speaking * ASA IV or greater * Psychiatric or cognitive disorders * Allergy/contraindications to protocol medications. * Renal insufficiency with Cr \> 2.0 or hepatic failure * Sensory/motor disorder involving the operative limb * PCS score \>20 * Patients with severe cardiac or neurological conditions precluding the use of study medications * Patients using anticoagulation other than aspirin for the 14-day period after discharge