Aromatherapy in Total Knee Replacement

October 29, 2026 updated by: Hospital for Special Surgery, New York

Aromatherapy for Post-operative Anxiety and Pain After Primary Unilateral Total Knee Replacement: A Pilot Randomized Controlled Trial

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.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

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.

Study Type

Interventional

Enrollment (Actual)

30

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • New York
      • New York, New York, United States, 10021
        • Hospital for Special Surgery

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 80 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Lavender-Peppermint Aromatherapy Group

This is the interventional group. Participants in this group will receive aromatherapy tabs in the scent of lavender-peppermint. Tabs will be worn on a badge for a total of 72 hours, and participants will replace the aroma tabs every 12 hours.
Other: Elequil Lavender-peppermint Aromatabs

100% pure essential oils Lavender-peppermint aromatabs purchased through Beekley Medical
Placebo Comparator: Almond-oil Aromatherapy Group

This is the placebo group. Participants in this group will receive aromatherapy tabs in the scent of almond oil. Tabs will worn on a badge for a total of 72 hours, and participants will replace the aroma tabs every 12 hours.
Other: Elequil Almond-Oil Aromatabs

100% pure essential oils Almond-oil aromatabs purchased through Beekley Medical

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
State Trait Anxiety Inventory
Time Frame: Measured pre-operatively, in the post-anesthesia care unit (PACU), post-operative day (POD) 1, POD 2, POD 3, POD 7

To assess the change in participants' anxiety level before and each individual day after surgery. Measured using the State-Trait Anxiety Inventory (STAI).

STATE anxiety, with higher scores being worse:

For calm, at ease, relaxed, steady:

4 = not at all 3 = somewhat 2 = moderately so

1 = very much so

For tense, worrying over misfortunes, frightened, nervous, jittery, worried:

  1. = not at all
  2. = somewhat
  3. = moderately so
  4. = very much so

TRAIT anxiety, with higher scores being worse:

For self satisfaction, feeling secure, being steady:

4=almost never 3=sometimes 2=often

1=almost always

For nervous/restless, wishing to be happier, feeling like a failure, worrying too much, lacking self confidence, feeling inadequate, feeling tension:

  1. almost never
  2. sometimes
  3. often
  4. almost always

STAI is scored as a sum of the scores for state and trait, with 20 being the lowest score (better outcome) and 80 being the highest score (worse outcome).
Measured pre-operatively, in the post-anesthesia care unit (PACU), post-operative day (POD) 1, POD 2, POD 3, POD 7
Patient-Reported Outcomes Measurement Information System (PROMIS) Anxiety Short Form 8a Version 1.0
Time Frame: Measured pre-operatively and on post-operative day (POD) 7

To assess participants' preoperative (cumulative 7 days before surgery) and postoperative (cumulative 7 days after surgery) anxiety. Measured using the PROMIS anxiety short form 8a Version 1.0. Scored on the following scale:

  1. = never
  2. = rarely
  3. = sometimes
  4. = often
  5. = always with 1 being the lowest score and 5 being the highest scores.

PROMIS anxiety short form 8a Version 1.0 is scored by calculating the sum of the scores for each question, and using the PROMIS conversion matrix to report the T-score (The T-score is a standardized metric where the United States general population mean is set to 50 with a standard deviation (SD) of 10. Higher T-scores indicate greater levels of anxiety.)
Measured pre-operatively and on post-operative day (POD) 7
Numeric Rating Scale Pain Scores
Time Frame: Measured pre-operatively, in the post-anesthesia care unit (PACU), post-operative day (POD) 1, POD 2, POD 3, POD 7

To assess the average pain score of participants after surgery. Measured using the numerical rating scale (NRS). Measured on a 11-point numeric scale from '0' representing one pain extreme (e.g. "no pain") to '10' representing the other pain extreme (e.g. "pain as bad as you can imagine" or "worst pain imaginable").
Measured pre-operatively, in the post-anesthesia care unit (PACU), post-operative day (POD) 1, POD 2, POD 3, POD 7

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Patient-Reported Outcomes Measurement Information System (PROMIS) Depression Short Form 8a
Time Frame: Measured pre-operatively and on post-operative day (POD) 7

To assess participants' post-operative emotional distress. Measured using the PROMIS depression short form 8a. Scored on the following scale:

  1. = never
  2. = rarely
  3. = sometimes
  4. = often
  5. = always with 1 being the lowest score and 5 being the highest scores.

Scored by calculating the sum of the scores for each question, and using the PROMIS conversion matrix to report the T-score. (The T-score is a standardized metric where the United States general population mean is set to 50 with a standard deviation (SD) of 10. Higher T-scores indicate greater levels of anxiety.)
Measured pre-operatively and on post-operative day (POD) 7
Pain Catastrophizing Scale
Time Frame: Measured pre-operatively, post-operative day (POD) 1, POD 2, POD 3, POD 7

The Pain Catastrophizing Scale is made up of 13 phrases that describe various thoughts and sensations that people may have while they are in pain. The items are assessed on a 5-point scale and are grouped into three categories: rumination (4 questions), magnification (3 questions), and helplessness (6 questions). Scored on the following scale:

0 = Not at all

  1. = To a slight degree
  2. = To a moderate degree
  3. = To a great degree
  4. = All the time with 0 being the lowest and 4 being the highest score.

Scored as the sum of all questions, and the sum of the scores for each question within each subscale. The range for Total Sum: 0 to 52, Rumination: 0 to 16, Magnification: 0 to 12, Helplessness: 0 to 24
Measured pre-operatively, post-operative day (POD) 1, POD 2, POD 3, POD 7
Patient-Reported Outcomes Measurement Information System (PROMIS) Short Form (SF) v1.1 Pain Interference
Time Frame: Measured pre-operatively and on post-operative day (POD) 7

The PROMIS SF v1.1 Pain Interference instruments (adult) measure the self-reported consequences of pain on relevant aspects of a person's life and may include the extent to which pain hinders engagement with social, cognitive, emotional, physical, and recreational activities. Pain Interference also incorporates items probing sleep and enjoyment in life, though the item bank only contains one sleep item. The Pain Interference items utilize a 7-day recall period (items include the phrase "the past 7 days"). Scored on the following scale:

  1. = Not at all
  2. = A little bit
  3. = Somewhat
  4. = Quite a bit
  5. = Very much With 1 being the lowest and 5 being the highest

Scored by calculating the sum of the scores for each question, and using the PROMIS conversion matrix to report the T-score. (The T-score is a standardized metric where the United States general population mean is set to 50 with a standard deviation (SD) of 10. Higher T-scores indicate greater levels of anxiety.)
Measured pre-operatively and on post-operative day (POD) 7
Post-operative Opioid Consumption
Time Frame: Measured in the post-operative care unit (PACU), post-operative day (POD) 1, POD2, POD3, POD7

Self-reported measure of medication, dosage, and time of opioid consumption. Reported as Morphine Milligram equivalents.
Measured in the post-operative care unit (PACU), post-operative day (POD) 1, POD2, POD3, POD7
Number of Participants With Post-operative Nausea
Time Frame: Measured at post-anesthesia care unit (PACU), post-operative day (POD) 1, POD 2, POD 3, POD 7

To assess if participants experience post-operative nausea. Measured using the Opioid Related Symptom Distress Scale question: In the past 24 hours, I had nausea (yes/no).
Measured at post-anesthesia care unit (PACU), post-operative day (POD) 1, POD 2, POD 3, POD 7
Number of Participants With Post-operative Vomiting
Time Frame: Measured at post-anesthesia care unit (PACU), post-operative day (POD) 1, POD 2, POD 3, POD 7

To assess if participants experience post-operative vomiting. Measured using the Opioid Related Symptom Distress Scale question: In the past 24 hours, I had vomiting (yes/no).
Measured at post-anesthesia care unit (PACU), post-operative day (POD) 1, POD 2, POD 3, POD 7
Incidences of Post-operative Complications
Time Frame: Measured at post-anesthesia care unit (PACU) up to post operative day 7

To assess the incidences of post-operative complications such as need for ICU admission, DVT/PE, MI, stroke.

To be measured in the number of patients who reported adverse events.
Measured at post-anesthesia care unit (PACU) up to post operative day 7
Opioid-related Symptom Distress Scale
Time Frame: Measured at post-anesthesia care unit (PACU), post-operative day (POD) 1, POD 2, POD 3, POD 7

The Opioid-Related Symptom Distress Scale (ORSDS) assesses opioid-related symptoms across the dimensions of frequency, severity, and bothersomeness. According to the scoring manual, Clinically Meaningful Events (CMEs) are calculated using the symptom severity items only. Severity is rated on a 5-point scale ranging from 0 (did not have symptom) to 4 (very severe). Therefore, scores range from 0 to 4, with higher scores indicating greater symptom severity.
Measured at post-anesthesia care unit (PACU), post-operative day (POD) 1, POD 2, POD 3, POD 7
Participants' Satisfaction With the Aromatherapy
Time Frame: Measured at post operative day 7

Self-reported responses on a survey of 7-items to assess participants' level of satisfaction with the aromatherapy they received.

Measured on the following scales:

  1. = Not satisfied/no prior knowledge or experience/ not at all/ no
  2. = A little bit/a little knowledge or experience/to a slight degree
  3. = Moderately/moderate knowledge or experience/to a moderate degree
  4. = Quite a bit/considerable knowledge or experience/to a great degree
  5. = Extremely satisfied/expert knowledge or regular application/all of the time/ yes with 1 being the lowest and 5 being the highest.
Measured at post operative day 7
Aromatab Adherence
Time Frame: Measured on post operative day (POD) 1, POD2, POD3.

Feasibility was assessed as the number of Participants that reported "Yes" to wearing each aromatab.
Measured on post operative day (POD) 1, POD2, POD3.
Hospital Length of Stay
Time Frame: Measured at discharge as number of hours elapsed between post anesthesia care unit entry and discharge time

Hospital length of stay was measured as hours elapsed from post anesthesia care unit entry to discharge, assessed up to 7 days.
Measured at discharge as number of hours elapsed between post anesthesia care unit entry and discharge time
Bang Blinding Index
Time Frame: Measured on postoperative day 7

The Bang Blinding Index ranges from -1 to 1, where index of 0 indicates random guessing (perfect blinding, better outcome), 1 indicates complete unblinding (all guesses are correct, worse outcome), and -1 indicates complete opposite guessing (all guesses are incorrect, worse outcome). Patients were asked to guess whether the patient was given the intervention (Lavender-Peppermint) or Control (Almond Oil) Aromatherapy. For each arm, calculation of the index score involves subtracting the proportion of respondents assigned to that arm who guess incorrectly from the proportion that guessed correctly.
Measured on postoperative day 7

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Hospital for Special Surgery, New York

Investigators

  • Principal Investigator: Uchenna Umeh, MD, Hospital for Special Surgery, New York

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

October 3, 2023

Primary Completion (Actual)

April 1, 2024

Study Completion (Actual)

April 1, 2024

Study Registration Dates

First Submitted

September 13, 2023

First Submitted That Met QC Criteria

September 13, 2023

First Posted (Actual)

September 21, 2023

Study Record Updates

Last Update Posted (Actual)

November 3, 2026

Last Update Submitted That Met QC Criteria

October 29, 2026

Last Verified

January 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2023-1715

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

There is no plan to make IPD available to other researchers.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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