Study to Examine Pain Relief With Supplemental Intrathecal Morphine in TKA Patients
Study to Examine Pain Relief With Supplemental Intrathecal Morphine in TKA Patients
This is a prospective, randomized, double-blinded, placebo-controlled study designed to
 examine pain relief following intrathecal morphine sulfate (0.2mg) in patients undergoing
 total knee arthroplasty (TKA) under spinal anesthesia in addition to a femoral nerve
 catheter. The protocol consists of two parts: (1) a prospective patient recruitment study and
 (2) a retrospective assay for endocannabinoids on previously collected specimens.
This is a prospective, case-controlled randomized, double-blinded, placebo-controlled study
 expected to enroll up to 100 patients scheduled to undergo unilateral total knee arthroplasty
 (TKA) under regional anesthesia (defined as intrathecal spinal + femoral nerve blockade +
 femoral nerve catheter for post-operative analgesia) at Stony Brook Hospital. The patients
 were randomized to receive either IT morphine 0.2 mg (Group 1) or placebo (Group 2) in
 combination with their standard-of-care spinal anesthesia. Post-operatively, the patients
 were given an intravenous patient-controlled analgesic opioid for breakthrough pain.

 Only the pharmacist preparing the drug/placebo has knowledge of how each subject was
 randomized. Study staff completed multiple questionnaires regarding subjects' pain scores and
 patient disability from pain to assess changes between different study periods (ie.
 pre-operative, post-operative and follow up). Biological samples were also taken from each
 subject to measure and analyze differences and changes in endocannabinoid levels.
Inclusion Criteria:

 -  Scheduled for unilateral TKA under regional anesthesia

 -  ASA Class 1, 2 or 3

 -  Able to give informed consent

 -  Able to understand English

 Exclusion Criteria:

 -  Medical condition(s) that prevents use of regional anesthesia (e.g. infection at site
 of injection, coagulopathy, severe hypovolemia, severe aortic or mitral stenosis,
 increased intracranial pressure, severe spinal deformity, spinal cord hardware or
 stimulator implanted)

 -  Allergy to morphine

 -  Morbid obesity (BMI > 45)

 -  Respiratory compromise (difficult airway, severe emphysema or COPD)

 -  Obstructive sleep apnea (only if diagnosed in a sleep disorders clinic and CPAP was
 prescribed)

 -  Chronic pain with opioid usage over 100 mg morphine-equivalents po/day

 -  History of abuse of opioids or other drugs of abuse

 -  Scheduled for bilateral TKA

 -  Revision of knee arthroplasty

 -  Any medical condition that would affect the patient's ability to metabolize or excrete
 the study drugs (e.g. chronic kidney failure with patient on dialysis) or other
 medical condition that in the investigator's opinion would render the patient
 unsuitable for this research study