Aromatherapy in Total Knee Replacement

The purpose of this pilot randomized controlled trial is to investigate the effects of aromatherapy on postoperative anxiety and pain in total knee replacement patients. The primary research questions are:

Does Lavender-Peppermint Aromatherapy reduce post operative anxiety in patients after primary total knee replacement when compared to placebo?

Does Lavender-Peppermint Aromatherapy reduce post operative pain in patient after primary total knee replacement when compared to placebo?

Participants will be assigned to one of the following groups at random:

* Intervention: Aromatherapy with the lavender-peppermint scent
* Control: Aromatherapy with the almond oil scent

Participants will also be asked to complete pre- and post-operative questionnaires.

Researchers will compare both groups (intervention vs control) to see if aromatherapy reduces post-operative anxiety and/or pain.

Preoperative depression, anxiety, and catastrophizing have all been linked to an increase in postoperative pain and opiate use. Although aromatherapy, specifically lavender, may lower anxiety, no placebo-controlled trial has been undertaken to establish Aromatherapy's therapeutic promise for anxiety after total knee replacement. Although peppermint has been demonstrated to reduce nausea and vomiting, it has not been tested in this population for post-operative nausea and vomiting (PONV). The purpose of this pilot randomized controlled study is to determine the effectiveness of Lavender-Peppermint in reducing post-operative anxiety and discomfort in patients following unilateral primary knee replacement surgery.

The primary research questions are:

Does Lavender-Peppermint Aromatherapy reduce post operative anxiety in patients after primary total knee replacement when compared to placebo?

Does Lavender-Peppermint Aromatherapy reduce post operative pain in patient after primary total knee replacement when compared to placebo?

Participants will be assigned to one of the following groups at random:

* Intervention: Aromatherapy in the lavender-peppermint scent
* Control: Aromatherapy in the almond oil scent

Participants will also be asked to complete pre- and post-operative questionnaires via the following surveys/questionnaires:

* State-Trait Anxiety Inventory Short Form
* PROMIS Anxiety v1.0 (short form 8a)
* PROMIS Depression v1.0 (short form 8a)
* PROMIS Pain Interference v1.1 (short form 6b)
* Pain Catastrophizing Scale
* Pain Rating Scale in Numeric Form
* Opioid Consumption
* Opioid Related Symptoms Distress Scale
* Adverse Events
* Aromatherapy Satisfaction Questionnaire
* Bang Blinding Index

Researchers will compare both groups (intervention vs control) to see if aromatherapy reduces post-operative anxiety and/or pain.

Eligibility Criteria:
Inclusion Criteria:

* Age \> 18 and ≤ 80
* Scheduled to undergo primary, unilateral knee replacement surgery
* Willing and able to provide informed consent
* Willing and able to complete follow-up procedures
* Intact olfactory function
* Score 19 or greater on the PROMIS Anxiety Shortform 8A

Exclusion Criteria:

* Score \<19 on the PROMIS Emotional Distress - Anxiety - Short Form 8a
* Current major anxiety or depression
* Currently taking medications to treat anxiety
* Impaired sense of smell
* History of chronic pain with opioid use for greater than 3 months
* History of Drug or Alcohol abuse
* History of fibromyalgia
* History of G6PD deficiency
* Plant or tree nut allergy
* Severe allergy to Opioids, NSAIDS or local anesthetics (such as anaphylaxis)
* Severe liver disease, renal insufficiency (with inability to take acetaminophen or NSAIDS)
* Non-English Speaking
* Surgery requiring a hospitalization of greater than 3 days
* Patient refusal
* Current cardiac fibrillation
* Chronic opioid user (\>3 months)
* BMI ≥ 45
* Contraindication to neuraxial anesthesia