Reducing Perioperative Oxidative Stress to Prevent Postoperative Chronic Pain Following Total Knee Arthroplasty

Inclusion Criteria:

* Age 50 or older
* Intact cognitive status and ability to provide informed consent (based on cognitive screening with the Mini Mental State Examination)
* Ability to read and write in English sufficiently to understand and complete study questionnaires
* Undergoing unilateral primary TKA
* Medical diagnosis of osteoarthritis
* Past 24 hour worst numeric rating scale (NRS) pain of at least 4/10.

Exclusion Criteria:

* Diagnosis of pre-existing neuropathy
* Untreated hypo/hyperthyroidism
* Untreated heart disease
* Alanine transaminase/aspartate transaminase \>2x upper-limit of normal range
* serum creatinine \>1.5 mg/dl
* Pregnancy
* Complex Regional Pain Syndrome (CRPS) diagnosis prior to undergoing TKA
* Presence of lower extremity vascular disease, inflammatory or autoimmune disorders, or malignancy
* Presence of current clinically significant chronic pain conditions outside of the lower extremity ( daily pain for \>3 months and greater ≥3/10 in intensity or the focus of medical care)
* Presence of other medical conditions that in the opinion of the orthopedic surgeon co-investigators would make a patient's study participation unsafe