Does Duloxetine Reduce Sub-Acute Pain After Knee Arthroplasty?

Inclusion Criteria:

- Patients with osteoarthritis scheduled for primary tricompartmental total knee
arthroplasty with a participating surgeon

- Age 25 to 75 years

- Planned use of regional anesthesia

- Ability to follow study protocol

- English speaking (primary outcome obtained via telephone call and secondary outcomes
include questionnaires validated in English only)

- Patients planning on being discharged home or to a rehabilitation center that has
agreed to participate

Exclusion Criteria:

- Concurrent use of duloxetine or other SNRIs, MAOIs, Tricyclic antidepressants,
triptans (sumatriptan, rizatriptan, naratriptan, zolmitriptan, eletriptan,
almotriptan, frovatriptan), lithium, buspirone, St. John's Wort

- Hepatic insufficiency

- Renal insufficiency

- Patients younger than 25 years old and older than 75

- Patients intending to receive general anesthesia

- Allergy or intolerance to one of the study medications

- Patients with an ASA of IV

- Chronic gabapentin/pregabalin use (regular use for longer than 3 months)

- Chronic opioid use (taking opioids for longer than 3 months)

- Patients with major prior ipsilateral open knee surgery