Pain Perception During Intra-Articular Knee Joint Injection: What is the Effect of Needle Gauge and the Use of Ethyl Chloride?

June 26, 2026 updated by: University of California, Davis

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.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

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 Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
88

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 4

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
    • California
      • Sacramento, California, United States, 95817
        • UC Davis Sports Medicine Clinic
        • Contact:
        • Contact:
        • Principal Investigator:
          • Daniel Herman, MD, PhD
        • Sub-Investigator:
          • Kevin Nasre, DO, MS

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  1. age ≥ 40 years
  2. fulfillment of the American College of Rheumatology criteria for knee OA
  3. confirmation of knee-related pain and/or functional loss by clinical examination.

  4. Patients with either

    1. bilateral knee OA/injections, or
    2. unilateral knee OA/injections.
  5. Agreed to an intra-articular knee joint injection with steroids
  6. Naive to use of ethyl chloride

Exclusion Criteria:

  1. Arthroscopy of the index knee(s) within the prior 6 months
  2. Steroid injection of the knee(s) within the prior 3 months
  3. Hyaluronic acid or platelet-rich plasma injection of the knee within the prior 6 months
  4. Patient reported prior injection of any type with ethyl chloride spray
  5. Knee effusion requiring aspiration at the time of the procedure
  6. Cognitively impaired individuals

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: Health Services Research
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: 22 Gauge Needle WITH Ethyl Chloride spray
This group will receive an intra-articular knee joint injection using a 22 gauge needle, and will be pre-anesthetized with ethyl chloride spray
Procedure: 22 gauge needle
This intervention will observe patients post-procedural pain using a 22 gauge needle
Procedure: +/- Ethyl Chloride Topical Aerosol Anesthetic
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.
Experimental: 25 Gauge Needle WITH Ethyl Chloride spray
This group will receive an intra-articular knee joint injection using a 25 gauge needle, and will be pre-anesthetized with ethyl chloride spray
Procedure: +/- Ethyl Chloride Topical Aerosol Anesthetic
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.
Procedure: 25 gauge needle
This intervention will observe patients post-procedural pain using a 25 gauge needle
Placebo Comparator: 22 Gauge Needle WITHOUT Ethyl Chloride spray
This group will receive an intra-articular knee joint injection using a 22 gauge needle, and will be pre-anesthetized with a PLACEBO spray
Procedure: 22 gauge needle
This intervention will observe patients post-procedural pain using a 22 gauge needle
Procedure: +/- Ethyl Chloride Topical Aerosol Anesthetic
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.
Placebo Comparator: 25 Gauge Needle WITHOUT Ethyl Chloride spray
This group will receive an intra-articular knee joint injection using a 25 gauge needle, and will be pre-anesthetized with a PLACEBO spray
Procedure: +/- Ethyl Chloride Topical Aerosol Anesthetic
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.
Procedure: 25 gauge needle
This intervention will observe patients post-procedural pain using a 25 gauge needle

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
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)
immediately following the procedure

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
NRPS pain 24-48 hours after the procedure at the injection site, assessing injection-related "soreness"
Time Frame: 28-48 hours after the procedure
NRPS = "Numeric Rating of Pain Scale", scale from 0 to 100. "0" = minimum score, better outcome); "100" (maximum score, worse outcome)
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

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)
6 weeks following procedure

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of California, Davis

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Department of Physical Medicine and Rehabilitation

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 (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
August 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 1, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
February 13, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 3, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
March 7, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 29, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 26, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2200055

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

Yes

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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