Dronabinol in Total Knee Arthroplasty (TKA)

The primary outcome of the study will be cumulative patient opioid consumption 24-48 hours post operatively, defined by total morphine equivalents (MEs). This outcome will be measured starting at recovery room entry and conclude at 48 hours after anesthesia stop time.

Time to reach discharge physical therapy goals, as defined by the number of hours required to meet the following criteria: stable vital signs during Physical therapy (PT), safe independent transfer from bed to standing as well as transfer in and out of seated position, ability to walk 40 feet only with aid of crutch or walker. This outcome will be measured prior to patient discharge.

Patient pain with ambulation on postoperative day (POD) 1, 2, 7, 90 and 180, defined by patient reported Numeric Rating Scale (NRS) pain score, (from 0-no pain to 10-worst pain imaginable).

Patient pain at rest upon PACU entry and in the morning of postoperative day (POD)1, POD2, POD7, POD90 and POD180 defined by patient reported Numeric Rating Scale (NRS) pain score, (from 0-no pain to 10-worst pain imaginable).

Patient pain during morning physical therapy on postoperative day (POD)1 and 2, defined by patient reported Numeric Rating Scale (NRS) pain score, (from 0-no pain to 10-worst pain imaginable).

Hospital length of stay from procedure start time to time of discharge

Postoperative desaturation events are defined as the number of times oxygen saturation dropped below 88% for at least 20 seconds or more. The number of such events will be counted per subject during the monitoring period, beginning in the immediate postoperative period on postoperative day (POD)0 (in the PACU) and will continue until the end post operative day 2/patient discharge, whichever occurs first. Oxygen desaturation is defined when measured SpO2 is less than 88%. Measurements will only be recorded if the desaturation event happens for 20 seconds or longer.

PainOut assesses post-surgical pain by collecting data on pain intensity, interference with daily activities, and other related factors. Questionnaire uses multiple scales from 0 (none/not at all/did not interfere/extremely dissatisfied) to 10 (extreme/severe/worst pain imaginable/completely interfered/extremely satisfied). Pain severity/Interference/Symptom questions are scored from 0-10, with higher scores indicating worse outcomes. With a scale of 0-10, higher scores indicate better outcomes for the following questions: decision participation question and satisfaction question.

The following questions used a scale of 1-11, where 1=0% and 11=100%:

Pain relief (a higher percentage indicates better outcome) Time with severe pain (a higher percentage indicates worse outcome)

The following questions used a scale of Yes/No, reporting number of patients with Yes

• Been out of bed since surgery
• Would have liked more pain treatment
• Received information about pain treatment
• Used non-medicine methods to relieve pain
• Persistent painful condition for 3 months or more

DN4 questionnaire to assess neuropathic pain on postoperative day (POD)1, 2, 7, 90 and 180. The DN4 questionnaire is a series of Yes or No questions that revolves around the characteristics that may suggest the presence or development of neuropathic conditions/pain (burning, painful cold, electric shocks, tingling, pins and needles, numbness, itching, hypoesthesia to touch, hypoesthesia to pinprick, pain increased by brushing). Total score is calculated by summing the total of the individual question scores, for a total score range of 0-10, with a score of greater than or equal to 4 indicating the patient may be suffering from neuropathic pain.

The Opioid-Related Symptom Distress Scale (ORSDS) is a scale that assesses three dimensions of symptom distress (frequency, severity, and bothersomeness) for 12 symptoms. The symptom-specific ORSDS is calculated by taking the average of the three symptom distress dimensions. The composite score will be reported for postoperative day (POD)1 and POD2. If a patient denies experiencing a particular symptom, their response will be coded as 0.

If they do:

Frequency will be assessed using a 4 point scale:

• rarely
• occasionally
• frequently
• almost constantly

with 1 being the lowest and 4 being the highest.

Severity is assessed using a 4 point scale:

• slight
• moderate
• severe
• very severe

with 1 being the lowest and 4 being the highest.

Bothersomeness is assessed using a 5 point scale:

• not at all
• a little bit
• somewhat
• quite a bit
• very much

with 1 being the lowest and 5 being the highest.

Patient consumption of non-opioid analgesics in the post-anesthesia care unit (PACU) and on postoperative day (POD)1, POD2, POD7. This was measured for acetaminophen, ibuprofen, ketorolac, meloxicam, naproxen, and gabapentin as yes/no. Number of participants who report "yes" for each non-opioid analgesic is reported.

Sleep disturbance via actigraphy measurement using the ActiGraph wGT3X-BT activity monitor. Measured during the first 24 hours postoperatively.

Sleep disturbance via actigraphy measurement using the ActiGraph wGT3X-BT activity monitor. Wake After Sleep Onset is the duration of time a patient was awake after falling asleep and before getting out of bed. Measured during the first 24 hours postoperatively.

Sleep disturbance via actigraphy measurement using the ActiGraph wGT3X-BT activity monitor. Sleep Efficiency is the ratio between total sleep time and the total time in bed. Measured during the first 24 hours postoperatively. Sleep Efficiency ratio is expressed as a percentage, where higher values represent better outcomes.

Sleep disturbance via actigraphy measurement using the ActiGraph wGT3X-BT activity monitor. Measured as number of awakenings during the first 24 hours postoperatively.

Measured as yes/no for a series of 13 questions asking patients if they have experienced any: change of mood, difficulty with memory, slurring of speech, blurred vision, hallucinations, increased awareness of surroundings, palpitations, headache, dizziness, drowsiness, dry mouth, involuntary muscle twitching, or tremors. Number of participants who report "yes" for each symptom is reported.

Measured in the post-anesthesia care unit (PACU), between PACU exist and midnight (Post-op), postoperative day (POD)1, POD2

Opioid consumption measured in morphine milligram equivalents in the post-anesthesia care unit and postoperative day 1 (analyzed as 0-24 hours after surgery)

Number of participants reporting opioid use at postoperative day 90.