Osteoarthritis (OA) of the KneePhase 4NCT06865170
Pain Perception During Intra-Articular Knee Joint Injection: What is the Effect of Needle Gauge and the Use of Ethyl Chloride?
A Phase 4 study testing 25 gauge needle, 22 gauge needle and +/- Ethyl Chloride Topical Aerosol Anesthetic in people with Osteoarthritis (OA) of the Knee and Fear of Needles, run by University of California, Davis at 1 site in United States.
Trial summary
This study aims to investigate factors that affect the subjective experience of pain during and after intra-articular knee joint injection of steroids by comparing needle gauge size (22 G vs 25 G needles), as well as the presence or absence of topical ethyl chloride spray. Read more about this study
- Who is it for?
- Ages 40 to 89 yearsHealthy volunteers can take part
- Conditions the study is for
- Osteoarthritis (OA) of the Knee, Fear of Needles
- What is being tested?
- 25 gauge needle, 22 gauge needle and +/- Ethyl Chloride Topical Aerosol Anesthetic
- Type of treatment
- Injection or infusion, Surgery or procedure
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 88 participants
- Where
- 1 siteUnited States
- Study dates
- Dec 2026to Dec 2026
- Phase
- Phase 4
- 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 40 to 89 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- age ≥ 40 years
- fulfillment of the American College of Rheumatology criteria for knee OA
- confirmation of knee-related pain and/or functional loss by clinical examination.
- Patients with either
- bilateral knee OA/injections, or
- unilateral knee OA/injections.
- Agreed to an intra-articular knee joint injection with steroids
- Naive to use of ethyl chloride
Who cannot join
- Arthroscopy of the index knee(s) within the prior 6 months
- Steroid injection of the knee(s) within the prior 3 months
- Hyaluronic acid or platelet-rich plasma injection of the knee within the prior 6 months
- Patient reported prior injection of any type with ethyl chloride spray
- Knee effusion requiring aspiration at the time of the procedure
- Cognitively impaired individuals
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
UC Davis Sports Medicine Clinic
Sacramento, California, 95817
Daniel Herman, MD, PhD, 919-641-2724, dcherman@ucdavis.edu
Kevin Nasre, DO, MS, 650-787-3723, knasre@ucdavis.edu
About this study
This study aims to investigate factors that affect the subjective experience of pain during and after intra-articular knee joint injection of steroids by comparing needle gauge size (22 G vs 25 G needles), as well as the presence or absence of topical ethyl chloride spray. Additionally, this study will investigate the effects of other various factors on patients' pain associated with the injection. Lastly, this study aims to determine the effect of patients' subjective pain from the injection on long-term clinical outcomes.
Specific aims are as follows:
Read more
Aim 1): Determine the effect of needle gauge size on patient reported pain associated with an ultrasound-guided intra-articular knee injection.
Aim 2): Determine the effect of ethyl chloride spray on patient reported pain associated with an ultrasound-guided intra-articular knee injection.
Aim 3): Determine the effect of sex, age, BMI, thigh size, severity of OA, and fear of needles on patient pain associated with an ultrasound-guided intra-articular knee injection.
Aim 4) Determine the effect of patient pain from the procedure on longer term clinical outcomes after an ultrasound-guided intra-articular knee steroid injection.
Researchers will obtain data at various time points, including pre-procedural data, immediately after the procedure, 24-48 hours after, and 6 weeks post-procedure.
Participants will:
Consent to receiving an intra-articular knee joint injection with steroids if indicated.
Score their "procedural" pain immediately following the procedure, score their post-procedural "soreness" 24-48 hours after via telephone call, and score their overall knee pain about 6 weeks after the procedure via telephone call.
Read the detailed description
Hypotheses to be tested:
Hypothesis 1): Patients who receive an ultrasound-guided intra-articular knee steroid injection with a 25G needle will report less pain from the procedure at the time of the procedure and less procedure-related pain 24-48 hours after the procedure
Hypothesis 2) Patients who receive an ultrasound-guided intra-articular knee steroid injection with use of ethyl chloride with a given needle gauge will report less pain from the procedure at the time of the procedure and 24-48 hours after the procedure
Hypothesis 3) Higher thigh circumference and fear of needles will be associated with higher levels of pain from the procedure at the time of the procedure and 24-48 hours after the procedure
Hypothesis 4) Higher levels of patient pain during the injection procedure will be associated with lower improvements in knee osteoarthritis pain and knee functional scores at 6 weeks.
There is evidence to suggest that by effectively altering certain parameters and techniques such as needle gauge diameter, speed of administration, and angle of needle during subcutaneous injection of local anesthetic, one can effectively improve the subjective experience of the patient. Evidence also suggests that choice of needle gauge size - which is at the discretion of the practitioner - may be inversely proportional to patient's perception of pain during an injection procedure. Topical anesthesia, such as via the use of ethyl chloride spray (which is also at the discretion of the practitioner), may also modify procedural pain. Furthermore, some studies suggest a correlation between patients' pain during a procedure and their clinical outcomes from the injection.
However, the current research is primarily composed of studies investigating subcutaneous injections (e.g. insulin or vaccination injections) using relatively small needle gauges, or of anesthetic injections in the spine. As such, there is very limited research on factors which may impact peripheral joint injections. Furthermore, there is a paucity of information regarding the effect of patient factors such as age, sex, limb size, anxiety, and fear of needles on the perception of pain during peripheral intra-articular injections.
Additional knowledge regarding the use of different needle gauge and/or the use of local anesthetic may help guide physician treatment patterns with the goal of optimizing patient satisfaction. Additionally, by obtaining subjective data at multiple time points, including 6 weeks post-injection, investigators hope to determine if differences in patient experience with the procedure is associated with patient outcomes.
- Conditions
- Osteoarthritis (OA) of the Knee, Fear of Needles
- Being tested
- 25 gauge needle, 22 gauge needle, +/- Ethyl Chloride Topical Aerosol Anesthetic
- Keywords
- pain perception, fear of needles, needle gauge, ethyl chloride, corticosteroid injection, 25G versus 22G
- Medical subject headings
- Osteoarthritis, Iatrophobia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
25 gauge needleProcedure or surgery
This intervention will observe patients post-procedural pain using a 25 gauge needle
22 gauge needleProcedure or surgery
This intervention will observe patients post-procedural pain using a 22 gauge needle
+/- Ethyl Chloride Topical Aerosol AnestheticProcedure or surgery
This intervention will observe patients post-procedural pain when using topical ethyl chloride spray. This will be compared to a placebo spray which will utilize isopropyl alcohol.
| Study group | Role | What they receive |
|---|---|---|
| 22 Gauge Needle WITH Ethyl Chloride spray | Experimental | This group will receive an intra-articular knee joint injection using a 22 gauge needle, and will be pre-anesthetized with ethyl chloride spray Receives: Procedure: 22 gauge needle; Procedure: +/- Ethyl Chloride Topical Aerosol Anesthetic |
| 25 Gauge Needle WITH Ethyl Chloride spray | Experimental | This group will receive an intra-articular knee joint injection using a 25 gauge needle, and will be pre-anesthetized with ethyl chloride spray Receives: Procedure: 25 gauge needle; Procedure: +/- Ethyl Chloride Topical Aerosol Anesthetic |
| 22 Gauge Needle WITHOUT Ethyl Chloride spray | Placebo comparator | This group will receive an intra-articular knee joint injection using a 22 gauge needle, and will be pre-anesthetized with a PLACEBO spray Receives: Procedure: 22 gauge needle; Procedure: +/- Ethyl Chloride Topical Aerosol Anesthetic |
| 25 Gauge Needle WITHOUT Ethyl Chloride spray | Placebo comparator | This group will receive an intra-articular knee joint injection using a 25 gauge needle, and will be pre-anesthetized with a PLACEBO spray Receives: Procedure: 25 gauge needle; Procedure: +/- Ethyl Chloride Topical Aerosol Anesthetic |
What is being measured
The primary outcome is the main question the study is designed to answer.
NRPS for injection-related pain at the time of the procedure
NRPS = "Numeric Rating of Pain Scale", scale from 0 to 100. "0" = minimum score, better outcome); "100" (maximum score, worse outcome)
Measured: immediately following the procedure
Secondary outcomes (2)
NRPS pain 24-48 hours after the procedure at the injection site, assessing injection-related "soreness"
NRPS = "Numeric Rating of Pain Scale", scale from 0 to 100. "0" = minimum score, better outcome); "100" (maximum score, worse outcome)
Measured: 28-48 hours after the procedure
NPRS score for overall knee pain, and WOMAC functional scores at six weeks post-procedure
NRPS = "Numeric Rating of Pain Scale", scale from 0 to 100. "0" = minimum score, better outcome); "100" (maximum score, worse outcome).
WOMAC = "Western Ontario and McMaster Universities Arthritis Index" is a self-administered questionnaire consisting of 24 items divided into 3 subscales. Test questions are scored on a scale of 0-4, which correspond to: None (0), Mild (1), Moderate (2), Severe (3), and Extreme (4)
Measured: 6 weeks following procedure
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted7 Mar 2025
- Study startDec 2026 (estimated)
- Primary completionDec 2026 (estimated)
- Study completionDec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Osteoarthritis (OA) of the KneeStudies of the same condition, open and under way.
- More trials run by University of California, DavisThe sponsor's other registered studies.
- 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 4
- Primary purpose
- Health services research
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 88 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of California, Davis
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06865170
- Sponsor's protocol ID
- 2200055
- Status last verified
- Sep 2026
- First submitted
- 13 Feb 2025
- Last updated
- 16 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 16 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Pain Perception During Intra-Articular Knee Joint Injection: What is the Effect of Needle Gauge and the Use of Ethyl Chloride?
- ClinicalTrials.gov ID
- NCT06865170
- Acronym / sponsor ID
- 2200055
- Conditions
- Osteoarthritis (OA) of the Knee, Fear of Needles
- Keywords
- pain perception, fear of needles, needle gauge, ethyl chloride, corticosteroid injection, 25G versus 22G
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 88 participants (estimated)
- Lead sponsor
- University of California, DavisUniversity, hospital or other
- Study start
- Dec 2026 (estimated)
- Primary completion
- Dec 2026 (estimated)
- Study completion
- Dec 2026 (estimated)
- First posted
- 7 Mar 2025 (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.
This study aims to investigate factors that affect the subjective experience of pain during and after intra-articular knee joint injection of steroids by comparing needle gauge size (22 G vs 25 G needles), as well as the presence or absence of topical ethyl chloride spray. Additionally, this study will investigate the effects of other various factors on patients' pain associated with the injection. Lastly, this study aims to determine the effect of patients' subjective pain from the injection on long-term clinical outcomes.
Specific aims are as follows:
Aim 1): Determine the effect of needle gauge size on patient reported pain associated with an ultrasound-guided intra-articular knee injection.
Aim 2): Determine the effect of ethyl chloride spray on patient reported pain associated with an ultrasound-guided intra-articular knee injection.
Aim 3): Determine the effect of sex, age, BMI, thigh size, severity of OA, and fear of needles on patient pain associated with an ultrasound-guided intra-articular knee injection.
Aim 4) Determine the effect of patient pain from the procedure on longer term clinical outcomes after an ultrasound-guided intra-articular knee steroid injection.
Researchers will obtain data at various time points, including pre-procedural data, immediately after the procedure, 24-48 hours after, and 6 weeks post-procedure.
Participants will:
Consent to receiving an intra-articular knee joint injection with steroids if indicated.
Score their "procedural" pain immediately following the procedure, score their post-procedural "soreness" 24-48 hours after via telephone call, and score their overall knee pain about 6 weeks after the procedure via telephone call.
Detailed description
Hypotheses to be tested:
Hypothesis 1): Patients who receive an ultrasound-guided intra-articular knee steroid injection with a 25G needle will report less pain from the procedure at the time of the procedure and less procedure-related pain 24-48 hours after the procedure
Hypothesis 2) Patients who receive an ultrasound-guided intra-articular knee steroid injection with use of ethyl chloride with a given needle gauge will report less pain from the procedure at the time of the procedure and 24-48 hours after the procedure
Hypothesis 3) Higher thigh circumference and fear of needles will be associated with higher levels of pain from the procedure at the time of the procedure and 24-48 hours after the procedure
Hypothesis 4) Higher levels of patient pain during the injection procedure will be associated with lower improvements in knee osteoarthritis pain and knee functional scores at 6 weeks.
There is evidence to suggest that by effectively altering certain parameters and techniques such as needle gauge diameter, speed of administration, and angle of needle during subcutaneous injection of local anesthetic, one can effectively improve the subjective experience of the patient. Evidence also suggests that choice of needle gauge size - which is at the discretion of the practitioner - may be inversely proportional to patient's perception of pain during an injection procedure. Topical anesthesia, such as via the use of ethyl chloride spray (which is also at the discretion of the practitioner), may also modify procedural pain. Furthermore, some studies suggest a correlation between patients' pain during a procedure and their clinical outcomes from the injection.
However, the current research is primarily composed of studies investigating subcutaneous injections (e.g. insulin or vaccination injections) using relatively small needle gauges, or of anesthetic injections in the spine. As such, there is very limited research on factors which may impact peripheral joint injections. Furthermore, there is a paucity of information regarding the effect of patient factors such as age, sex, limb size, anxiety, and fear of needles on the perception of pain during peripheral intra-articular injections.
Additional knowledge regarding the use of different needle gauge and/or the use of local anesthetic may help guide physician treatment patterns with the goal of optimizing patient satisfaction. Additionally, by obtaining subjective data at multiple time points, including 6 weeks post-injection, investigators hope to determine if differences in patient experience with the procedure is associated with patient outcomes.
Study design
- Primary purpose
- Health services research
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| 22 Gauge Needle WITH Ethyl Chloride spray | Experimental | Procedure: 22 gauge needle, Procedure: +/- Ethyl Chloride Topical Aerosol AnestheticThis group will receive an intra-articular knee joint injection using a 22 gauge needle, and will be pre-anesthetized with ethyl chloride spray |
| 25 Gauge Needle WITH Ethyl Chloride spray | Experimental | Procedure: 25 gauge needle, Procedure: +/- Ethyl Chloride Topical Aerosol AnestheticThis group will receive an intra-articular knee joint injection using a 25 gauge needle, and will be pre-anesthetized with ethyl chloride spray |
| 22 Gauge Needle WITHOUT Ethyl Chloride spray | Placebo comparator | Procedure: 22 gauge needle, Procedure: +/- Ethyl Chloride Topical Aerosol AnestheticThis group will receive an intra-articular knee joint injection using a 22 gauge needle, and will be pre-anesthetized with a PLACEBO spray |
| 25 Gauge Needle WITHOUT Ethyl Chloride spray | Placebo comparator | Procedure: 25 gauge needle, Procedure: +/- Ethyl Chloride Topical Aerosol AnestheticThis group will receive an intra-articular knee joint injection using a 25 gauge needle, and will be pre-anesthetized with a PLACEBO spray |
Who may qualify
- Ages
- 40 to 89 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (8 listed)
- age ≥ 40 years
- fulfillment of the American College of Rheumatology criteria for knee OA
- confirmation of knee-related pain and/or functional loss by clinical examination.
- Patients with either
- Agreed to an intra-articular knee joint injection with steroids
Key exclusion criteria (6 listed)
- Arthroscopy of the index knee(s) within the prior 6 months
- Steroid injection of the knee(s) within the prior 3 months
- Hyaluronic acid or platelet-rich plasma injection of the knee within the prior 6 months
- Patient reported prior injection of any type with ethyl chloride spray
- Knee effusion requiring aspiration at the time of the procedure
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 |
|---|---|---|
| 25 gauge needleThis intervention will observe patients post-procedural pain using a 25 gauge needle | Procedure or surgery | 25 Gauge Needle WITH Ethyl Chloride spray, 25 Gauge Needle WITHOUT Ethyl Chloride spray |
| 22 gauge needleThis intervention will observe patients post-procedural pain using a 22 gauge needle | Procedure or surgery | 22 Gauge Needle WITH Ethyl Chloride spray, 22 Gauge Needle WITHOUT Ethyl Chloride spray |
| +/- Ethyl Chloride Topical Aerosol AnestheticThis intervention will observe patients post-procedural pain when using topical ethyl chloride spray. This will be compared to a placebo spray which will utilize isopropyl alcohol. | Procedure or surgery | 22 Gauge Needle WITH Ethyl Chloride spray, 22 Gauge Needle WITHOUT Ethyl Chloride spray, 25 Gauge Needle WITH Ethyl Chloride spray, 25 Gauge Needle WITHOUT Ethyl Chloride spray |
Primary outcome
NRPS for injection-related pain at the time of the procedure
Time frame: immediately following the procedure
NRPS = "Numeric Rating of Pain Scale", scale from 0 to 100. "0" = minimum score, better outcome); "100" (maximum score, worse outcome)
2 secondary outcomes
NRPS pain 24-48 hours after the procedure at the injection site, assessing injection-related "soreness"
Time frame: 28-48 hours after the procedure
NPRS score for overall knee pain, and WOMAC functional scores at six weeks post-procedure
Time frame: 6 weeks following procedure
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 16 Sep 2026.
- Individual participant dataSharing planned: Undecided
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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.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing 25 gauge needle, 22 gauge needle and +/- Ethyl Chloride Topical Aerosol Anesthetic in people with Osteoarthritis (OA) of the Knee and Fear of Needles, run by University of California, Davis 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 8 inclusion and 6 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 16 Sep 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 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
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?
Each site lists its own contact: choose the nearest one under Trial locations. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
NRPS for injection-related pain at the time of the procedure (time frame: immediately following the procedure). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 16 Sep 2026.