OsteoarthitisPhase 2NCT07638189
CBD Knee Osteoarthritis Study
A Phase 2 study testing Cannabidiol (CBD) in people with Osteoarthitis, run by University of Tennessee at 1 site in United States.
Trial summary
Osteoarthritis of the knee is a common cause of pain in the US. The currently available medicines for knee osteoarthritis sometimes are not effective at relieving the pain or have unacceptable side effects. Thus, alternate pain relieving treatments are needed. Read more about this study
- Who is it for?
- Ages 21 years and older
- Conditions the study is for
- Osteoarthitis
- What is being tested?
- Cannabidiol (CBD)
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 30 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Jul 2026to 30 Mar 2028
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 21 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Knee OA (grade 2-3 as measured by the Kellgren-Lawrence Classification)
- OA knee pain on the Visual Analog Pain Scale > 4 in either knee
- Receiving treatment at one of the eight Campbell Clinic Orthopaedics locations
Who cannot join
- Other forms of arthritis such as psoriatic arthritis or rheumatoid arthritis due to different sources of inflammation in these conditions
- Allergies to CBD or Castor Oil
- Current opioid use
- BMI of over 40
- Those who cannot walk without an assistance device (e.g., walker)
- Those who are currently on knee injections (i.e. cortisol or hyaluronic acid gel) for knee pain
Show all 13Show fewer
- Patients scheduled for a knee replacement in the next 3-6 months
- Active cannabis or CBD use
- Alcohol consumption > 21 alcoholic drinks each week
- Active pregnancy, nursing, or actively planning a pregnancy
- Active chronic liver or renal disease
- Active depression/suicidality
- Medications that interact with CBD in the liver that cannot be discontinued 14. Discretion of the Multiple Principal Investigators for concerns regarding noncompliance with the study intervention.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site
University of Tennessee Health Science Center
Memphis, Tennessee, 38163
Karen C Johnson, MD, MPH
Karen Derefinko, PhD
About this study
Official title: Pilot Study Using Topical Cannabidiol (CBD) to Manage Osteoarthritic Knee Pain
Osteoarthritis of the knee is a common cause of pain in the US. The currently available medicines for knee osteoarthritis sometimes are not effective at relieving the pain or have unacceptable side effects. Thus, alternate pain relieving treatments are needed.
CBD, an active chemical from the hemp derived cannabis sativa plant, has received a lot of attention for its potential pain relieving properties, but there has been limited research to find out if topically applied CBD can decrease pain from knee osteoarthritis. CBD lacks the psychoactive effects seen with marijuana use, because it does not contain THC which is responsible for those effects in marijuana. It is legal to use CBD in the State of Tennessee (site of study).
Read more
The CBD Knee Study is sponsored by the University of Tennessee Health Science Center and is a collaborative effort between doctors at UT and Campbell Clinic. In the CBD Knee Study, the investigators are examining whether topically applied CBD dissolved in Castor Oil will relieve knee pain in persons with knee osteoarthritis.
Persons who take part in the study would need to come for study visits, fill out questionnaires about their health and knee pain, and would be asked to use the topical study oil on their knees. Taking part in the CBD Knee Study is voluntary.
Read the detailed description
Chronic pain is an enormous burden worldwide, impacting more than 30% of the population. Osteoarthritis (OA) is the most common form of joint disfunction and pain, affecting 33 million people in the United States. OA is a prominent cause of pain for older individuals, particularly knee pain. Due to the chronic and progressive nature of OA pain, many patients require long-term analgesic management. Non-steroidal anti-inflammatory drugs (NSAIDs), are commonly used to treat moderate pain from OA, but side effects and numerous potential drug interactions limit use in many individuals. Not surprisingly, opioids became a part of treatment for OA pain in the early 2000s, and have been commonly used for many years even though opioids are not recommend for use by osteoarthritis guideline committees due to their potential risk of misuse, abuse and overdose. With limitations on currently available treatments such as NSAIDs and opioids, the field is now exploring alternative analgesics to manage chronic osteoarthritis pain.
Medical marijuana and cannabis have long been used to treat chronic pain disorders and there is increasing interest to explore cannabinoids as alternate pain therapy. Cannabidiol (CBD), an active cannabinoid from hemp derived cannabis sativa, has garnered attention as a strong pharmaceutical candidate for analgesia. For example, in two recent systematic reviews, CBD was found to be beneficial for treating chronic pain and appeared to improve sleep and Quality of Life (QOL) for persons with chronic pain. CBD lacks the psychoactive effects seen with marijuana use, because it does not contain Δ9- tetrahydrocannabinol (THC) responsible for those effects in marijuana. These properties make CBD a clear candidate for an alternative treatment for chronic pain syndromes such as knee OA.
However, rigorous CBD research is limited in certain chronic pain populations such as persons with OA, but there are some data suggesting benefits. A cross-sectional study, in a large sample of individuals who used oral CBD for arthritis (n=428), showed that 83% reported a reduction in pain following CBD use, and 61% reported a reduction or cessation of other medications, including opioids (18%). There are, however, notable limitations in previous research on CBD for chronic pain that should be acknowledged. Many previous CBD research studies have focused primarily on orally administered CBD often at low doses, which undergoes first-pass metabolism in the liver, reducing bioavailability and potentially diminishing therapeutic effects. Additionally, much of the research relied on the use of over the counter (OTC) CBD products at lower doses, with unverified or untested purity and quality. Thus, additional research on CBD for pain relief is warranted in persons with knee OA. Topical CBD that avoids the first pass metabolism of oral routes has also been shown to reduce chronic pain. In a small randomized clinical trial (n=15) in patients with symptomatic peripheral neuropathy pain, topical CBD Oil use (250 mg / 3 fl. Oz - Higher Dose) resulted in a statistically significant reduction in intense pain, sharp pain and cold/itchy sensations compared with a placebo with no adverse events reported. In another placebo controlled crossover clinical trial in thumb basal joint osteoarthritis, patients had significant reductions in pain after 2 weeks of topical CBD (6.2 mg/ml BID - Lower Dose) administration vs. shea butter (placebo). Another pilot study (n=18) in individuals with hand OA found that topical transdermal CBD gel applied three times daily significantly decreased pain scores (p<0.0001), improved grip strength (p<0.0001), and alleviated stiffness. These findings suggest that topical CBD could represent a promising option for managing chronic localized pain conditions like knee OA. Despite this promising preliminary work, to our knowledge there are no studies using topical CBD at therapeutic doses to treat knee pain in persons with OA to definitively establish efficacy.
There is also a need for a vehicle to deliver the topical CBD dose to the knee area for maximal effect. Castor Oil is an excellent choice. Castor Oil is an odorless vegetable oil made from the seeds of the Castor plant. Castor Oil is already used as a vehicle to assist with delivery of FDA approved topical pain relief medications such as diclofenac sodium (NSAID) to the area of intended use. The main constituent of Castor Oil is ricinoleic acid, which may also have anti-inflammatory and analgesic effects. Thus, Castor Oil is a clear choice as a vehicle to deliver topical CBD to the site of pain in persons with knee OA.
Given healthcare challenges to manage chronic pain, including avoiding opioids because of their addictive potential, investigation of topically applied CBD dissolved in a vehicle such as Castor Oil may provide a promising alternative therapy for the reduction of OA pain of the knee, while having an exceptional safety profile. However, additional research on topical CBD+Castor Oil using rigorous study designs is needed to document efficacy and safety for the treatment of OA pain of the knee.
To address this issue, the investigators will conduct a pilot randomized crossover clinical trial to examine the analgesic efficacy of topical CBD+Castor Oil compared to a topical Castor Oil alone. 30 patients with OA pain of the knee will be randomized. The investigators anticipate 60 patients will sign consent and screen to randomize 30 patients.
SPECIFIC AIMS
Aim 1: Examine medication analgesic efficacy within subjects (n=30) in a balanced crossover design where each participant receives both treatments in randomized order with a 2-week washout period in between. Participants will be randomized to (1) CBD+Castor Oil followed by Castor Oil alone; or 2) Castor Oil alone followed by CBD+Castor Oil. Each oil will be used for a total of 1 month. Hypothesis 1: CBD+Castor Oil will have reduced knee pain scores compare to Castor Oil alone.
Aim 2: Examine changes in knee function, sleep, and knee Quality Of Life (QOL) by medication condition. Hypothesis 2: CBD+Castor Oil will have higher knee function, reduced sleep disturbance scores, and higher QOL than Castor Oil alone.
The investigators hypothesize that with adequate analgesic properties and low safety concerns, topical CBD+Castor Oil may be extremely useful to manage chronic OA knee pain while improving knee function, QOL, and sleep.
- Conditions
- Osteoarthitis
- Being tested
- Cannabidiol (CBD), Castor Oil (Placebo)
- Keywords
- Randomized Clinical Trial, Cannabidiol (CBD), Knee Pain
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Cannabidiol (CBD)Dietary supplement
250 mg of CBD will be dissolved in 1 ml of Castor Oil. Participants will use 1ml of this solution on each knee BID
Castor Oil (Placebo)Other
1 ml of Castor oil alone will be applied to each knee BID as the placebo
| Study group | Role | What they receive |
|---|---|---|
| CBD+Castol Oil | Active comparator | 250 mg CBD dissolved in 1 ml of Castor Oil to be applied topically to the knee BID Receives: Dietary Supplement: Cannabidiol (CBD) |
| Castor Oil Alone | Placebo comparator | 1 ml of Castor Oil Alone applied topically to the knee as the placebo comparator BID Receives: Other: Castor Oil (Placebo) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Knee Pain
The investigators will use ecological momentary assessment to collect knee pain scores and develop pain trajectories. A Visual Analog Scale of Self-Reported Pain will be assessed at study visits and up to once a day via text message using the Wong-Baker visual analogue scale. A score of 0 is no pain and a score of 10 is severe pain. Please note this is crossover clinical trial and there are 2 Baseline Visits (One and Two).
Knee Pain will be assessed at the Screening Visit as an eligibility criteria and at Baseline One Visit (Day 1), Follow-up One Visit (Day 30), Baseline Two Visit (Day 44), and Follow-up Two Visit (Day 74). The Baseline One Visit will occur 2 weeks after the Screening Visit.
Change in knee pain scores on the Visual Analog Scale of Self-Reported Pain will be assessed from the Baseline One Visit to the the Follow-up One Visit and from the Baseline Two Visit to the the Follow-up Two Visit.
Measured: Day 1 - Baseline One Visit, Day 30 - Follow-up One Visit, Day 44 - Baseline Two Visit, and Day 74 - Follow-up Two Visit
Secondary outcomes (2)
Sleep
The PROMIS (Patient-Reported Outcomes Information System) Sleep Questionnaire will be used to assess sleep disturbance and sleep related impairment over the past 7 days. The questionnaire is divided into two distinct short-form assessments: 1) PROMIS Sleep Disturbance and 2) PROMIS Sleep-Related Impairment. The PROMIS sleep questionnaire utilizes a standardized T-score metric where the general U.S. population average is 50, with a standard deviation of 10. Higher scores indicate a greater severity of the concept being measured (e.g., more sleep disturbance or more sleep-related impairment). Below 55 is within normal limits, 55-59.9 is mild, 60-69.9 is moderate, and 70 and above is severe. Please note this is crossover clinical trial and there are 2 Baseline Visits (One and Two). Sleep will be assessed at the Baseline One Visit (Day 1), Follow-up One Visit (Day 30), Baseline Two Visit (Day 44), and Follow-up Two Visit (Day 74).
Measured: Day 1 - Baseline One Visit, Day 30 - Follow-up One Visit, Day 44 - Baseline Two Visit, and Day 74 - Follow-up Two Visit
Knee Related Quality of Life and Function
The Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaire will be used to assess five knee dimensions: pain, symptoms, activities of daily living (ADL), sport and recreation function, and knee-related quality of life. Each dimension is scored from 0 to 100, with 0 indicating extreme problems and 100 indicating no problems.
Please note this is crossover clinical trial and there are 2 Baseline Visits (One and Two). Knee Related Quality of Life and Function as measured by the KOOS questionnaire will be assessed at the Baseline One Visit (Day 1), Follow-up One Visit (Day 30), Baseline Two Visit (Day 44), and Follow-up Two Visit (Day 74). The Baseline One Visit will occur 2 weeks after the Screening Visit. The Follow-up One Visit will occur 1 month after the Baseline One Visit. The Baseline Two Visit will occur 2 weeks after the Follow-up One Visit. The Follow-up Two Visit will occur 1 month after the Baseline Two Visit.
Measured: Day 1 - Baseline One Visit, Day 30 - Follow-up One Visit, Day 44 - Baseline Two Visit, and Day 74 - Follow-up Two Visit
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Jun 2026
- Study start1 Jul 2026 (estimated)
- Primary completion20 Mar 2028 (estimated)
- Study completion30 Mar 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (74)Papers the sponsor has linked to this study.
- Other trials for OsteoarthitisStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- The investigators will conduct a pilot randomized crossover clinical trial (RCT) to examine the analgesic efficacy and safety of CBD+Castor Oil compared to a Castor Oil alone, in 30 patients with knee OA pain. Eligible participants will be randomized in a 1:1 fashion to either 1) CBD+Castor Oil followed by Castor Oil alone; or 2) Castor Oil alone followed by CBD+Castor Oil with a 2-week washout period between the treatment periods. Each oil will be used for a total of 1 month.
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Tennessee
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Karen Chandler Johnson, University of Tennessee
- Investigators
- Karen C Johnson, MD, MPH, Principal investigator, University of Tennessee
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07638189
- Sponsor's protocol ID
- STUDY00000389
- Status last verified
- Apr 2026
- First submitted
- 29 May 2026
- Last updated
- 10 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: The study will prepare and distribute a dataset. Confidentiality of individual participants will be maintained with all releases of data. The final study analytical database will be processed according to HIPAA definitions for public data sharing. During this process, the participant data will be de-identified by using processes which include but are not limited to: removal of identifiers, translation of dates and ages to delta time values, and assignment of random study identifiers. Out of this process will be a series of de-identified data files representing the final analytical data set. These data files will be provided in a standard format that is readable across a variety of applications and operating system platforms. Documentation that will be provided along with the data sharing file that may include but is not limited to: data dictionary, data code book, valid variable ranges, the protocol, MOP, and any electronic versions of any paper forms that were used in data collection.
Publications
Hall N, James B, Bhuiyan MAN, Crane E, Falgout C, Murnane KS. Topical cannabidiol is well tolerated in individuals with a history of elite physical performance and chronic lower extremity pain. J Cannabis Res. 2023 Mar 30;5(1):11. doi: 10.1186/s42238-023-00179-8.
PubMed 36991501Deyo RA, Hallvik SE, Hildebran C, Marino M, Dexter E, Irvine JM, O'Kane N, Van Otterloo J, Wright DA, Leichtling G, Millet LM. Association Between Initial Opioid Prescribing Patterns and Subsequent Long-Term Use Among Opioid-Naive Patients: A Statewide Retrospective Cohort Study. J Gen Intern Med. 2017 Jan;32(1):21-27. doi: 10.1007/s11606-016-3810-3. Epub 2016 Aug 2.
PubMed 27484682Bawa Z, Lewis D, Gavin PD, Libinaki R, Joubran L, El-Tamimy M, Taylor G, Meltzer R, Bedoya-Perez M, Kevin RC, McGregor IS. An open-label feasibility trial of transdermal cannabidiol for hand osteoarthritis. Sci Rep. 2024 May 23;14(1):11792. doi: 10.1038/s41598-024-62428-x.
PubMed 38783008Zehra A, Burns J, Liu CK, Manza P, Wiers CE, Volkow ND, Wang GJ. Cannabis Addiction and the Brain: a Review. J Neuroimmune Pharmacol. 2018 Dec;13(4):438-452. doi: 10.1007/s11481-018-9782-9. Epub 2018 Mar 19.
PubMed 29556883Yu L, Buysse DJ, Germain A, Moul DE, Stover A, Dodds NE, Johnston KL, Pilkonis PA. Development of short forms from the PROMIS sleep disturbance and Sleep-Related Impairment item banks. Behav Sleep Med. 2011 Dec 28;10(1):6-24. doi: 10.1080/15402002.2012.636266.
PubMed 22250775Roos EM, Lohmander LS. The Knee injury and Osteoarthritis Outcome Score (KOOS): from joint injury to osteoarthritis. Health Qual Life Outcomes. 2003 Nov 3;1:64. doi: 10.1186/1477-7525-1-64.
PubMed 14613558Villanueva MRB, Joshaghani N, Villa N, Badla O, Goit R, Saddik SE, Dawood SN, Rabih AM, Niaj A, Raman A, Uprety M, Calero M, Khan S. Efficacy, Safety, and Regulation of Cannabidiol on Chronic Pain: A Systematic Review. Cureus. 2022 Jul 16;14(7):e26913. doi: 10.7759/cureus.26913. eCollection 2022 Jul.
PubMed 35860716Towheed TE, Maxwell L, Judd MG, Catton M, Hochberg MC, Wells G. Acetaminophen for osteoarthritis. Cochrane Database Syst Rev. 2006 Jan 25;2006(1):CD004257. doi: 10.1002/14651858.CD004257.pub2.
PubMed 16437479Gidal BE, Vandrey R, Wallin C, Callan S, Sutton A, Saurer TB, Triemstra JL. Product labeling accuracy and contamination analysis of commercially available cannabidiol product samples. Front Pharmacol. 2024 Mar 18;15:1335441. doi: 10.3389/fphar.2024.1335441. eCollection 2024.
PubMed 38562466Crofford LJ. Use of NSAIDs in treating patients with arthritis. Arthritis Res Ther. 2013;15 Suppl 3(Suppl 3):S2. doi: 10.1186/ar4174. Epub 2013 Jul 24.
PubMed 24267197Karuppagounder V, Chung J, Abdeen A, Thompson A, Bouboukas A, Pinamont WJ, Yoshioka NK, Sepulveda DE, Raup-Konsavage WM, Graziane NM, Vrana KE, Elbarbary RA, Kamal F. Therapeutic Effects of Non-Euphorigenic Cannabis Extracts in Osteoarthritis. Cannabis Cannabinoid Res. 2023 Dec;8(6):1030-1044. doi: 10.1089/can.2021.0244. Epub 2022 Aug 22.
PubMed 35994012Patel VR, Dumancas GG, Kasi Viswanath LC, Maples R, Subong BJ. Castor Oil: Properties, Uses, and Optimization of Processing Parameters in Commercial Production. Lipid Insights. 2016 Sep 7;9:1-12. doi: 10.4137/LPI.S40233. eCollection 2016.
PubMed 27656091Losina E, Song S, Bensen GP, Katz JN. Opioid Use Among Medicare Beneficiaries With Knee Osteoarthritis: Prevalence and Correlates of Chronic Use. Arthritis Care Res (Hoboken). 2023 Apr;75(4):876-884. doi: 10.1002/acr.24844. Epub 2022 Nov 8.
PubMed 34919346Wongrakpanich S, Wongrakpanich A, Melhado K, Rangaswami J. A Comprehensive Review of Non-Steroidal Anti-Inflammatory Drug Use in The Elderly. Aging Dis. 2018 Feb 1;9(1):143-150. doi: 10.14336/AD.2017.0306. eCollection 2018 Feb.
PubMed 29392089Chesney E, McGuire P, Freeman TP, Strang J, Englund A. Lack of evidence for the effectiveness or safety of over-the-counter cannabidiol products. Ther Adv Psychopharmacol. 2020 Sep 9;10:2045125320954992. doi: 10.1177/2045125320954992. eCollection 2020.
PubMed 32973998
Study at a glance
From the registry record, last updated by the sponsor on 10 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Pilot Study Using Topical Cannabidiol (CBD) to Manage Osteoarthritic Knee Pain
- ClinicalTrials.gov ID
- NCT07638189
- Acronym / sponsor ID
- STUDY00000389
- Conditions
- Osteoarthitis
- Keywords
- Randomized Clinical Trial, Cannabidiol (CBD), Knee Pain
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- University of TennesseeUniversity, hospital or other
- Study start
- 1 Jul 2026 (estimated)
- Primary completion
- 20 Mar 2028 (estimated)
- Study completion
- 30 Mar 2028 (estimated)
- First posted
- 10 Jun 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Osteoarthritis of the knee is a common cause of pain in the US. The currently available medicines for knee osteoarthritis sometimes are not effective at relieving the pain or have unacceptable side effects. Thus, alternate pain relieving treatments are needed.
CBD, an active chemical from the hemp derived cannabis sativa plant, has received a lot of attention for its potential pain relieving properties, but there has been limited research to find out if topically applied CBD can decrease pain from knee osteoarthritis. CBD lacks the psychoactive effects seen with marijuana use, because it does not contain THC which is responsible for those effects in marijuana. It is legal to use CBD in the State of Tennessee (site of study).
The CBD Knee Study is sponsored by the University of Tennessee Health Science Center and is a collaborative effort between doctors at UT and Campbell Clinic. In the CBD Knee Study, the investigators are examining whether topically applied CBD dissolved in Castor Oil will relieve knee pain in persons with knee osteoarthritis.
Persons who take part in the study would need to come for study visits, fill out questionnaires about their health and knee pain, and would be asked to use the topical study oil on their knees. Taking part in the CBD Knee Study is voluntary.
Detailed description
Chronic pain is an enormous burden worldwide, impacting more than 30% of the population. Osteoarthritis (OA) is the most common form of joint disfunction and pain, affecting 33 million people in the United States. OA is a prominent cause of pain for older individuals, particularly knee pain. Due to the chronic and progressive nature of OA pain, many patients require long-term analgesic management. Non-steroidal anti-inflammatory drugs (NSAIDs), are commonly used to treat moderate pain from OA, but side effects and numerous potential drug interactions limit use in many individuals. Not surprisingly, opioids became a part of treatment for OA pain in the early 2000s, and have been commonly used for many years even though opioids are not recommend for use by osteoarthritis guideline committees due to their potential risk of misuse, abuse and overdose. With limitations on currently available treatments such as NSAIDs and opioids, the field is now exploring alternative analgesics to manage chronic osteoarthritis pain.
Medical marijuana and cannabis have long been used to treat chronic pain disorders and there is increasing interest to explore cannabinoids as alternate pain therapy. Cannabidiol (CBD), an active cannabinoid from hemp derived cannabis sativa, has garnered attention as a strong pharmaceutical candidate for analgesia. For example, in two recent systematic reviews, CBD was found to be beneficial for treating chronic pain and appeared to improve sleep and Quality of Life (QOL) for persons with chronic pain. CBD lacks the psychoactive effects seen with marijuana use, because it does not contain Δ9- tetrahydrocannabinol (THC) responsible for those effects in marijuana. These properties make CBD a clear candidate for an alternative treatment for chronic pain syndromes such as knee OA.
However, rigorous CBD research is limited in certain chronic pain populations such as persons with OA, but there are some data suggesting benefits. A cross-sectional study, in a large sample of individuals who used oral CBD for arthritis (n=428), showed that 83% reported a reduction in pain following CBD use, and 61% reported a reduction or cessation of other medications, including opioids (18%). There are, however, notable limitations in previous research on CBD for chronic pain that should be acknowledged. Many previous CBD research studies have focused primarily on orally administered CBD often at low doses, which undergoes first-pass metabolism in the liver, reducing bioavailability and potentially diminishing therapeutic effects. Additionally, much of the research relied on the use of over the counter (OTC) CBD products at lower doses, with unverified or untested purity and quality. Thus, additional research on CBD for pain relief is warranted in persons with knee OA. Topical CBD that avoids the first pass metabolism of oral routes has also been shown to reduce chronic pain. In a small randomized clinical trial (n=15) in patients with symptomatic peripheral neuropathy pain, topical CBD Oil use (250 mg / 3 fl. Oz - Higher Dose) resulted in a statistically significant reduction in intense pain, sharp pain and cold/itchy sensations compared with a placebo with no adverse events reported. In another placebo controlled crossover clinical trial in thumb basal joint osteoarthritis, patients had significant reductions in pain after 2 weeks of topical CBD (6.2 mg/ml BID - Lower Dose) administration vs. shea butter (placebo). Another pilot study (n=18) in individuals with hand OA found that topical transdermal CBD gel applied three times daily significantly decreased pain scores (p<0.0001), improved grip strength (p<0.0001), and alleviated stiffness. These findings suggest that topical CBD could represent a promising option for managing chronic localized pain conditions like knee OA. Despite this promising preliminary work, to our knowledge there are no studies using topical CBD at therapeutic doses to treat knee pain in persons with OA to definitively establish efficacy.
There is also a need for a vehicle to deliver the topical CBD dose to the knee area for maximal effect. Castor Oil is an excellent choice. Castor Oil is an odorless vegetable oil made from the seeds of the Castor plant. Castor Oil is already used as a vehicle to assist with delivery of FDA approved topical pain relief medications such as diclofenac sodium (NSAID) to the area of intended use. The main constituent of Castor Oil is ricinoleic acid, which may also have anti-inflammatory and analgesic effects. Thus, Castor Oil is a clear choice as a vehicle to deliver topical CBD to the site of pain in persons with knee OA.
Given healthcare challenges to manage chronic pain, including avoiding opioids because of their addictive potential, investigation of topically applied CBD dissolved in a vehicle such as Castor Oil may provide a promising alternative therapy for the reduction of OA pain of the knee, while having an exceptional safety profile. However, additional research on topical CBD+Castor Oil using rigorous study designs is needed to document efficacy and safety for the treatment of OA pain of the knee.
To address this issue, the investigators will conduct a pilot randomized crossover clinical trial to examine the analgesic efficacy of topical CBD+Castor Oil compared to a topical Castor Oil alone. 30 patients with OA pain of the knee will be randomized. The investigators anticipate 60 patients will sign consent and screen to randomize 30 patients.
SPECIFIC AIMS
Aim 1: Examine medication analgesic efficacy within subjects (n=30) in a balanced crossover design where each participant receives both treatments in randomized order with a 2-week washout period in between. Participants will be randomized to (1) CBD+Castor Oil followed by Castor Oil alone; or 2) Castor Oil alone followed by CBD+Castor Oil. Each oil will be used for a total of 1 month. Hypothesis 1: CBD+Castor Oil will have reduced knee pain scores compare to Castor Oil alone.
Aim 2: Examine changes in knee function, sleep, and knee Quality Of Life (QOL) by medication condition. Hypothesis 2: CBD+Castor Oil will have higher knee function, reduced sleep disturbance scores, and higher QOL than Castor Oil alone.
The investigators hypothesize that with adequate analgesic properties and low safety concerns, topical CBD+Castor Oil may be extremely useful to manage chronic OA knee pain while improving knee function, QOL, and sleep.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- The investigators will conduct a pilot randomized crossover clinical trial (RCT) to examine the analgesic efficacy and safety of CBD+Castor Oil compared to a Castor Oil alone, in 30 patients with knee OA pain. Eligible participants will be randomized in a 1:1 fashion to either 1) CBD+Castor Oil followed by Castor Oil alone; or 2) Castor Oil alone followed by CBD+Castor Oil with a 2-week washout period between the treatment periods. Each oil will be used for a total of 1 month.
| Arm | Type | Receives |
|---|---|---|
| CBD+Castol Oil | Active comparator | Dietary Supplement: Cannabidiol (CBD)250 mg CBD dissolved in 1 ml of Castor Oil to be applied topically to the knee BID |
| Castor Oil Alone | Placebo comparator | Other: Castor Oil (Placebo)1 ml of Castor Oil Alone applied topically to the knee as the placebo comparator BID |
Who may qualify
- Ages
- 21 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Knee OA (grade 2-3 as measured by the Kellgren-Lawrence Classification)
- OA knee pain on the Visual Analog Pain Scale > 4 in either knee
- Receiving treatment at one of the eight Campbell Clinic Orthopaedics locations
Key exclusion criteria (13 listed)
- Other forms of arthritis such as psoriatic arthritis or rheumatoid arthritis due to different sources of inflammation in these conditions
- Allergies to CBD or Castor Oil
- Current opioid use
- BMI of over 40
- Those who cannot walk without an assistance device (e.g., walker)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Cannabidiol (CBD)250 mg of CBD will be dissolved in 1 ml of Castor Oil. Participants will use 1ml of this solution on each knee BID | Dietary supplement | CBD+Castol Oil |
| Castor Oil (Placebo)1 ml of Castor oil alone will be applied to each knee BID as the placebo | Other | Castor Oil Alone |
Primary outcome
Knee Pain
Time frame: Day 1 - Baseline One Visit, Day 30 - Follow-up One Visit, Day 44 - Baseline Two Visit, and Day 74 - Follow-up Two Visit
The investigators will use ecological momentary assessment to collect knee pain scores and develop pain trajectories. A Visual Analog Scale of Self-Reported Pain will be assessed at study visits and up to once a day via text message using the Wong-Baker visual analogue scale. A score of 0 is no pain and a score of 10 is severe pain. Please note this is crossover clinical trial and there are 2 Baseline Visits (One and Two). Knee Pain will be assessed at the Screening Visit as an eligibility criteria and at Baseline One Visit (Day 1), Follow-up One Visit (Day 30), Baseline Two Visit (Day 44), and Follow-up Two Visit (Day 74). The Baseline One Visit will occur 2 weeks after the Screening Visit. Change in knee pain scores on the Visual Analog Scale of Self-Reported Pain will be assessed from the Baseline One Visit to the the Follow-up One Visit and from the Baseline Two Visit to the the Follow-up Two Visit.
2 secondary outcomes
Sleep
Time frame: Day 1 - Baseline One Visit, Day 30 - Follow-up One Visit, Day 44 - Baseline Two Visit, and Day 74 - Follow-up Two Visit
Knee Related Quality of Life and Function
Time frame: Day 1 - Baseline One Visit, Day 30 - Follow-up One Visit, Day 44 - Baseline Two Visit, and Day 74 - Follow-up Two Visit
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 10 Jun 2026.
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- Background: PubMed 27484682Deyo RA, Hallvik SE, Hildebran C, Marino M, Dexter E, Irvine JM, O'Kane N, Van Otterloo J, Wright DA, Leichtling G, Millet LM. Association Between Initial Opioid Prescribing Patterns and Subsequent Long-Term Use Among Opioid-Naive Patients: A Statewide Retrospective Cohort Study. J Gen Intern Med. 2017 Jan;32(1):21-27. doi: 10.1007/s11606-016-3810-3. Epub 2016 Aug 2.
- Background: PubMed 38783008Bawa Z, Lewis D, Gavin PD, Libinaki R, Joubran L, El-Tamimy M, Taylor G, Meltzer R, Bedoya-Perez M, Kevin RC, McGregor IS. An open-label feasibility trial of transdermal cannabidiol for hand osteoarthritis. Sci Rep. 2024 May 23;14(1):11792. doi: 10.1038/s41598-024-62428-x.
- Background: PubMed 29556883Zehra A, Burns J, Liu CK, Manza P, Wiers CE, Volkow ND, Wang GJ. Cannabis Addiction and the Brain: a Review. J Neuroimmune Pharmacol. 2018 Dec;13(4):438-452. doi: 10.1007/s11481-018-9782-9. Epub 2018 Mar 19.
- Background: PubMed 22250775Yu L, Buysse DJ, Germain A, Moul DE, Stover A, Dodds NE, Johnston KL, Pilkonis PA. Development of short forms from the PROMIS sleep disturbance and Sleep-Related Impairment item banks. Behav Sleep Med. 2011 Dec 28;10(1):6-24. doi: 10.1080/15402002.2012.636266.
- Background: PubMed 14613558Roos EM, Lohmander LS. The Knee injury and Osteoarthritis Outcome Score (KOOS): from joint injury to osteoarthritis. Health Qual Life Outcomes. 2003 Nov 3;1:64. doi: 10.1186/1477-7525-1-64.
- Background: PubMed 35860716Villanueva MRB, Joshaghani N, Villa N, Badla O, Goit R, Saddik SE, Dawood SN, Rabih AM, Niaj A, Raman A, Uprety M, Calero M, Khan S. Efficacy, Safety, and Regulation of Cannabidiol on Chronic Pain: A Systematic Review. Cureus. 2022 Jul 16;14(7):e26913. doi: 10.7759/cureus.26913. eCollection 2022 Jul.
- Background: PubMed 16437479Towheed TE, Maxwell L, Judd MG, Catton M, Hochberg MC, Wells G. Acetaminophen for osteoarthritis. Cochrane Database Syst Rev. 2006 Jan 25;2006(1):CD004257. doi: 10.1002/14651858.CD004257.pub2.
- Background: PubMed 38562466Gidal BE, Vandrey R, Wallin C, Callan S, Sutton A, Saurer TB, Triemstra JL. Product labeling accuracy and contamination analysis of commercially available cannabidiol product samples. Front Pharmacol. 2024 Mar 18;15:1335441. doi: 10.3389/fphar.2024.1335441. eCollection 2024.
- Background: PubMed 24267197Crofford LJ. Use of NSAIDs in treating patients with arthritis. Arthritis Res Ther. 2013;15 Suppl 3(Suppl 3):S2. doi: 10.1186/ar4174. Epub 2013 Jul 24.
- Background: PubMed 35994012Karuppagounder V, Chung J, Abdeen A, Thompson A, Bouboukas A, Pinamont WJ, Yoshioka NK, Sepulveda DE, Raup-Konsavage WM, Graziane NM, Vrana KE, Elbarbary RA, Kamal F. Therapeutic Effects of Non-Euphorigenic Cannabis Extracts in Osteoarthritis. Cannabis Cannabinoid Res. 2023 Dec;8(6):1030-1044. doi: 10.1089/can.2021.0244. Epub 2022 Aug 22.
- Background: PubMed 27656091Patel VR, Dumancas GG, Kasi Viswanath LC, Maples R, Subong BJ. Castor Oil: Properties, Uses, and Optimization of Processing Parameters in Commercial Production. Lipid Insights. 2016 Sep 7;9:1-12. doi: 10.4137/LPI.S40233. eCollection 2016.
- Individual participant dataSharing planned: No. The study will prepare and distribute a dataset. Confidentiality of individual participants will be maintained with all releases of data. The final study analytical database will be processed according to HIPAA definitions for public data sharing. During this process, the participant data will be de-identified by using processes which include but are not limited to: removal of identifiers, translation of dates and ages to delta time values, and assignment of random study identifiers. Out of this process will be a series of de-identified data files representing the final analytical data set. These data files will be provided in a standard format that is readable across a variety of applications and operating system platforms. Documentation that will be provided along with the data sharing file that may include but is not limited to: data dictionary, data code book, valid variable ranges, the protocol, MOP, and any electronic versions of any paper forms that were used in data collection.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Karen C Johnson, MD, MPH principal investigator
University of Tennessee
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Cannabidiol (CBD) in people with Osteoarthitis, run by University of Tennessee at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 13 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 10 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Karen Derefinko, PhD (901-448-5900, kderefin@uthsc.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Knee Pain (time frame: Day 1 - Baseline One Visit, Day 30 - Follow-up One Visit, Day 44 - Baseline Two Visit, and Day 74 - Follow-up Two Visit). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07638189, which also lists 74 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 10 Jun 2026.