Post-op Ketamine Study

Evaluation of Post Operative Pain Following Primary Total Knee Arthroplasty (TKA) With Intraoperative Subanesthetic Ketamine Administration and Spinal Anesthesia

The purpose of this study is to establish the effect of sub-anesthetic dosing of ketamine with spinal anesthesia during total knee arthroplasty on post-operative pain and narcotic consumption. We hypothesize that sub-anesthetic ketamine will decrease post-operative pain and narcotic consumption and may secondarily lead to shorter lengths of stay, faster rehabilitation, improved postoperative outcomes and patient satisfaction.

Inclusion Criteria:

• 18 - 85 years of age
• ASA I - IV
• Undergoing primary unilateral elective total knee arthroplasty with spinal anesthesia

Exclusion Criteria:

• BMI over 40*
• Contraindication or allergy to opioid pain medication or ketamine*
• Daily opioid use for pain control before surgery in excess of systemic morphine equivalent to 10 mg*
• Ejection fraction (EF) less than 30%
• Creatinine clearance less than 30 mL/min*
• History of chronic liver failure
• Desire for nerve block or general anesthesia
• Any neurologic or psychiatric disorder (including bipolar disorder, post traumatic stress disorder, schizophrenia)
• Prior surgery on ipsilateral knee within the last 6 months
• Alcohol abuse