Knee OsteoarthritisNCT07876752
Clinical Importance of Occult Suprapatellar Effusion in Knee Osteoarthritis
An observational study of Knee Osteoarthritis, run by Mardin Artuklu University at 1 site in Turkey (Türkiye).
Trial summary
Small amounts of fluid in the knee joint may not always be visible during a standard ultrasound examination performed while the leg is relaxed. When the quadriceps muscle contracts, this fluid may move into the area above the kneecap and become visible. Read more about this study
- Who is it for?
- Ages 40 to 80 years
- Conditions the study is for
- Knee Osteoarthritis
- What is being tested?
- Static and Dynamic Suprapatellar Ultrasonography
- How many people
- 105 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 30 Nov 2026to 31 May 2027
- Phase
- Observational
- 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 80 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: The study population will consist of adults with symptomatic primary knee osteoarthritis attending the Physical Medicine and Rehabilitation outpatient clinic of Mardin Training and Research Hospital. Participants will be classified according to suprapatellar effusion findings obtained during static and quadriceps contraction ultrasound examinations.
Who may be able to join
- Age 40-80 years
- Clinical diagnosis of primary knee osteoarthritis and radiographic Kellgren-Lawrence grade 2, 3, or 4
- Pain in the knee to be evaluated
- Ability to perform voluntary quadriceps contraction and the 30-second chair stand test
- Provision of written informed consent
Who cannot join
- Inflammatory rheumatic disease, crystal arthropathy, or active joint infection
- Intra-articular injection into the evaluated knee within the previous 3 months
- History of major surgery on the evaluated knee
- Marked varus or valgus deformity
- Knee trauma within the previous 3 months
- Inability to perform adequate voluntary quadriceps contraction
- Neurological, cardiopulmonary, or other musculoskeletal disease that may substantially affect chair stand performance
- Pregnancy
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)1 site
Mardin Training and Research Hospital
Mardin, 47100
Taha Yasin YILDIRIM, M.D., +90 534 220 77 17, tyasinyildirim.ftr@gmail.com
About this study
Small amounts of fluid in the knee joint may not always be visible during a standard ultrasound examination performed while the leg is relaxed. When the quadriceps muscle contracts, this fluid may move into the area above the kneecap and become visible. This finding is referred to in this study as occult suprapatellar effusion.
The aim of this study is to determine whether occult suprapatellar effusion is associated with knee pain and physical function in people with knee osteoarthritis. Participants will undergo ultrasound examination first at rest and then during quadriceps contraction. Based on these findings, they will be classified as having effusion visible at rest, occult effusion visible only during muscle contraction, or no effusion in either condition.
Knee pain, self-reported symptoms and function, and chair stand performance will be compared among these groups. The study will also examine whether greater effusion depth is associated with more severe pain, greater functional limitation, and poorer physical performance. No treatment will be assigned as part of the study.
Read the detailed description
Joint effusion is an ultrasound-detectable inflammatory feature of knee osteoarthritis and may be associated with pain and functional limitation. However, a small effusion may remain undetected during a conventional static examination. Voluntary quadriceps contraction can increase intra-articular pressure and move joint fluid into the suprapatellar recess, allowing an otherwise occult effusion to become visible. The clinical relevance of this dynamic finding has not been clearly established.
This single-center, observational, cross-sectional study will evaluate the suprapatellar recess using ultrasound both at rest and during voluntary quadriceps contraction. Participants will be classified into three groups according to the ultrasound findings: static effusion, defined as effusion visible during the resting examination; occult effusion, defined as effusion absent at rest but visible during quadriceps contraction; and no effusion, defined as the absence of effusion under both conditions.
The primary comparison will evaluate 30-second chair stand performance between participants with occult effusion and those with no effusion. Additional analyses will compare pain, self-reported symptoms and function, and chair stand performance across all three groups. The relationships between suprapatellar effusion depth and clinical and functional outcomes will also be examined. Adjusted analyses will assess whether effusion group is independently associated with physical performance after accounting for age, body mass index, and radiographic osteoarthritis severity.
- Conditions
- Knee Osteoarthritis
- Being tested
- Static and Dynamic Suprapatellar Ultrasonography
- Keywords
- Joint Effusion, Ultrasonography, Quadriceps Muscle, Physical Functional Performance, Osteoarthritis, Knee
- Medical subject headings
- Osteoarthritis, Knee, Hydrarthrosis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Static and Dynamic Suprapatellar UltrasonographyDiagnostic test
The suprapatellar recess will be examined by ultrasound with the participant resting in the supine position and the knee extended. The examination will first be performed at rest and then repeated during voluntary quadriceps contraction while the probe position is maintained. The presence of effusion and its maximum anteroposterior depth in millimeters will be recorded under both conditions. This assessment is used only to classify ultrasound findings and does not involve treatment.
| Study group | Role | What they receive |
|---|---|---|
| Static Effusion Group | Participants with suprapatellar effusion visible during the resting static ultrasound examination. Receives: Diagnostic Test: Static and Dynamic Suprapatellar Ultrasonography | |
| Occult Effusion Group | Participants without suprapatellar effusion during the resting static examination but with effusion visible during voluntary quadriceps contraction. Receives: Diagnostic Test: Static and Dynamic Suprapatellar Ultrasonography | |
| No Effusion Group | Participants without suprapatellar effusion during either the resting static examination or voluntary quadriceps contraction. Receives: Diagnostic Test: Static and Dynamic Suprapatellar Ultrasonography |
What is being measured
The primary outcome is the main question the study is designed to answer.
Physical Performance Assessed by the 30-Second Chair Stand Test
The number of complete sit-to-stand repetitions performed within 30 seconds will be recorded. The score has a minimum of 0 repetitions and no predefined maximum. A higher number of repetitions indicates better lower-extremity physical performance. The primary comparison will be between the occult effusion group and the no effusion group.
Measured: Baseline
Secondary outcomes (3)
Knee Pain Intensity Assessed by the Numerical Rating Scale
Average knee pain intensity during the previous week will be assessed using an 11-point numerical rating scale ranging from 0 to 10. A score of 0 indicates no pain, and a score of 10 indicates the worst imaginable pain. Higher scores indicate greater knee pain intensity.
Measured: Baseline
Symptoms and Physical Function Assessed by the Western Ontario and McMaster Universities Osteoarthritis Index
The Western Ontario and McMaster Universities Osteoarthritis Index consists of 24 items scored from 0 to 4. It provides pain, stiffness, physical function, and total scores. Score ranges are 0-20 for pain, 0-8 for stiffness, 0-68 for physical function, and 0-96 for the total score. Higher scores indicate greater pain, stiffness, and functional limitation.
Measured: Baseline
Suprapatellar Effusion Depth Assessed by Ultrasonography
The maximum anteroposterior depth of suprapatellar effusion will be measured in millimeters during the resting static ultrasound examination and during voluntary quadriceps contraction. Each contraction measurement will be repeated twice, and the highest value will be recorded. The measurement has a minimum value of 0 millimeters and no predefined maximum. Higher values indicate greater effusion depth.
Measured: Baseline
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Oct 2026
- Study start30 Nov 2026 (estimated)
- Primary completion31 May 2027 (estimated)
- Study completion31 May 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for Knee OsteoarthritisStudies 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
- Observational
- Observational model
- Case only
- Time perspective
- Cross-sectional
- Enrolment
- 105 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Mardin Artuklu University
- Sponsor type
- University, hospital or other
- Collaborators
- Mardin Training and Research Hospital
- Responsible party
- Principal investigator, Taha Yasin YILDIRIM, Mardin Artuklu University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07876752
- Sponsor's protocol ID
- MEAH-PMR-TYY3
- Status last verified
- Oct 2026
- First submitted
- 9 Oct 2026
- Last updated
- 20 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Abbasi B, Pezeshki-Rad M, Akhavan R, Sahebari M. Association between clinical and sonographic synovitis in patients with painful knee osteoarthritis. Int J Rheum Dis. 2017 May;20(5):561-566. doi: 10.1111/1756-185X.12834. Epub 2016 Feb 23.
PubMed 26915050Cushman DM, Ross B, Teramoto M, English J, Joyner JR, Bosley J. Identification of Knee Effusions With Ultrasound: A Comparison of Three Methods. Clin J Sport Med. 2022 Jan 1;32(1):e19-e22. doi: 10.1097/JSM.0000000000000823.
PubMed 32032167Ike RW, Somers EC, Arnold EL, Arnold WJ. Ultrasound of the knee during voluntary quadriceps contraction: a technique for detecting otherwise occult effusions. Arthritis Care Res (Hoboken). 2010 May;62(5):725-9. doi: 10.1002/acr.20047.
PubMed 20461790
Study at a glance
From the registry record, last updated by the sponsor on 20 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Clinical Importance of Occult Suprapatellar Effusion in Knee Osteoarthritis
- ClinicalTrials.gov ID
- NCT07876752
- Acronym / sponsor ID
- MEAH-PMR-TYY3
- Conditions
- Knee Osteoarthritis
- Keywords
- Joint Effusion, Ultrasonography, Quadriceps Muscle, Physical Functional Performance, Osteoarthritis, Knee
- Study type
- Observational
- Recruitment status
- Not yet recruiting
- Enrolment
- 105 participants (estimated)
- Lead sponsor
- Mardin Artuklu UniversityUniversity, hospital or other
- Collaborators
- Mardin Training and Research Hospital
- Study start
- 30 Nov 2026 (estimated)
- Primary completion
- 31 May 2027 (estimated)
- Study completion
- 31 May 2027 (estimated)
- First posted
- 15 Oct 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.
Small amounts of fluid in the knee joint may not always be visible during a standard ultrasound examination performed while the leg is relaxed. When the quadriceps muscle contracts, this fluid may move into the area above the kneecap and become visible. This finding is referred to in this study as occult suprapatellar effusion.
The aim of this study is to determine whether occult suprapatellar effusion is associated with knee pain and physical function in people with knee osteoarthritis. Participants will undergo ultrasound examination first at rest and then during quadriceps contraction. Based on these findings, they will be classified as having effusion visible at rest, occult effusion visible only during muscle contraction, or no effusion in either condition.
Knee pain, self-reported symptoms and function, and chair stand performance will be compared among these groups. The study will also examine whether greater effusion depth is associated with more severe pain, greater functional limitation, and poorer physical performance. No treatment will be assigned as part of the study.
Detailed description
Joint effusion is an ultrasound-detectable inflammatory feature of knee osteoarthritis and may be associated with pain and functional limitation. However, a small effusion may remain undetected during a conventional static examination. Voluntary quadriceps contraction can increase intra-articular pressure and move joint fluid into the suprapatellar recess, allowing an otherwise occult effusion to become visible. The clinical relevance of this dynamic finding has not been clearly established.
This single-center, observational, cross-sectional study will evaluate the suprapatellar recess using ultrasound both at rest and during voluntary quadriceps contraction. Participants will be classified into three groups according to the ultrasound findings: static effusion, defined as effusion visible during the resting examination; occult effusion, defined as effusion absent at rest but visible during quadriceps contraction; and no effusion, defined as the absence of effusion under both conditions.
The primary comparison will evaluate 30-second chair stand performance between participants with occult effusion and those with no effusion. Additional analyses will compare pain, self-reported symptoms and function, and chair stand performance across all three groups. The relationships between suprapatellar effusion depth and clinical and functional outcomes will also be examined. Adjusted analyses will assess whether effusion group is independently associated with physical performance after accounting for age, body mass index, and radiographic osteoarthritis severity.
Study design
- Observational model
- Case only
- Time perspective
- Cross-sectional
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Static Effusion Group | – | Diagnostic Test: Static and Dynamic Suprapatellar UltrasonographyParticipants with suprapatellar effusion visible during the resting static ultrasound examination. |
| Occult Effusion Group | – | Diagnostic Test: Static and Dynamic Suprapatellar UltrasonographyParticipants without suprapatellar effusion during the resting static examination but with effusion visible during voluntary quadriceps contraction. |
| No Effusion Group | – | Diagnostic Test: Static and Dynamic Suprapatellar UltrasonographyParticipants without suprapatellar effusion during either the resting static examination or voluntary quadriceps contraction. |
Who may qualify
- Ages
- 40 to 80 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- The study population will consist of adults with symptomatic primary knee osteoarthritis attending the Physical Medicine and Rehabilitation outpatient clinic of Mardin Training and Research Hospital. Participants will be classified according to suprapatellar effusion findings obtained during static and quadriceps contraction ultrasound examinations.
Key inclusion criteria (5 listed)
- Age 40-80 years
- Clinical diagnosis of primary knee osteoarthritis and radiographic Kellgren-Lawrence grade 2, 3, or 4
- Pain in the knee to be evaluated
- Ability to perform voluntary quadriceps contraction and the 30-second chair stand test
- Provision of written informed consent
Key exclusion criteria (8 listed)
- Inflammatory rheumatic disease, crystal arthropathy, or active joint infection
- Intra-articular injection into the evaluated knee within the previous 3 months
- History of major surgery on the evaluated knee
- Marked varus or valgus deformity
- Knee trauma within the previous 3 months
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 |
|---|---|---|
| Static and Dynamic Suprapatellar UltrasonographyThe suprapatellar recess will be examined by ultrasound with the participant resting in the supine position and the knee extended. The examination will first be performed at rest and then repeated during voluntary quadriceps contraction while the probe position is maintained. The presence of effusion and its maximum anteroposterior depth in millimeters will be recorded under both conditions. This assessment is used only to classify ultrasound findings and does not involve treatment. | Diagnostic test | No Effusion Group, Occult Effusion Group, Static Effusion Group |
Primary outcome
Physical Performance Assessed by the 30-Second Chair Stand Test
Time frame: Baseline
The number of complete sit-to-stand repetitions performed within 30 seconds will be recorded. The score has a minimum of 0 repetitions and no predefined maximum. A higher number of repetitions indicates better lower-extremity physical performance. The primary comparison will be between the occult effusion group and the no effusion group.
3 secondary outcomes
Knee Pain Intensity Assessed by the Numerical Rating Scale
Time frame: Baseline
Symptoms and Physical Function Assessed by the Western Ontario and McMaster Universities Osteoarthritis Index
Time frame: Baseline
Suprapatellar Effusion Depth Assessed by Ultrasonography
Time frame: Baseline
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 20 Oct 2026.
- Background: PubMed 26915050Abbasi B, Pezeshki-Rad M, Akhavan R, Sahebari M. Association between clinical and sonographic synovitis in patients with painful knee osteoarthritis. Int J Rheum Dis. 2017 May;20(5):561-566. doi: 10.1111/1756-185X.12834. Epub 2016 Feb 23.
- Background: PubMed 32032167Cushman DM, Ross B, Teramoto M, English J, Joyner JR, Bosley J. Identification of Knee Effusions With Ultrasound: A Comparison of Three Methods. Clin J Sport Med. 2022 Jan 1;32(1):e19-e22. doi: 10.1097/JSM.0000000000000823.
- Background: PubMed 20461790Ike RW, Somers EC, Arnold EL, Arnold WJ. Ultrasound of the knee during voluntary quadriceps contraction: a technique for detecting otherwise occult effusions. Arthritis Care Res (Hoboken). 2010 May;62(5):725-9. doi: 10.1002/acr.20047.
- Individual participant dataSharing planned: No
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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?
An observational study of Knee Osteoarthritis, run by Mardin Artuklu University at 1 site in Turkey (Türkiye).
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 5 inclusion and 8 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 20 Oct 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 Turkey (Türkiye). 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. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
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 Taha Yasin YILDIRIM, M.D. (+90 534 220 77 17, tyasinyildirim.ftr@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Physical Performance Assessed by the 30-Second Chair Stand Test (time frame: Baseline). 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 NCT07876752, which also lists 3 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 20 Oct 2026.