Blood flow of the knee cap in patients with knee pain

ISRCTN	ISRCTN90377123
DOI	https://doi.org/10.1186/ISRCTN90377123
Secondary identifying numbers	NL77408.018.21

Submission date: 10/12/2021
Registration date: 15/12/2021
Last edited: 29/11/2023

Recruitment status: No longer recruiting
Overall study status: Completed
Condition category: Musculoskeletal Diseases

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Plain English summary of protocol

Background and study aims
Patellofemoral pain (pain at the front of your knee, around your kneecap) is a frequent and often long-standing painful condition of the knee. Although the available scientific evidence suggests that exercise therapy is an effective treatment, there are still a lot of patients who continue to suffer from knee pain. This study elaborates on a theory of disturbed bone blood flow in the bone of the knee cap. Reduced oxygen saturation of that specific tissue potentially explains the pain while prolonged sitting and descending stairs, but this has never been studied before. Therefore the aim of the study is to observe bone blood perfusion while the participant is seated (protocol 1) and simulates descending stairs (protocol 2). The oxygen saturation will be measured with a spectroscope, which is a non-invasive device and will be placed on the skin of the knee cap.

Who can participate?
Patients with patellofemoral pain and healthy persons can participate. Patellofemoral pain is defined as pain around or behind the knee cap and usually gets worse while descending stairs or during activities like running, jumping, and hopping. Before participating in this study the principal investigator will assess the presence of patellofemoral pain and exclude other conditions of the knee that could explain symptoms. Healthy persons are required to be completely pain-free and without other specific conditions like surgery in the past. Fulfillment of these requirements for healthy persons will also be assessed by the principal investigator prior to participation.

What does the study involve?
Persons who meet the criteria described above will be asked to stay seated for 15 minutes. Thereafter the spectroscope measurements will be started and the patient bends the knee to 90 degrees and will be asked to keep in that position for 30 minutes while the measurement of bone blood perfusion will take place (protocol 1). Thereafter, the participant will be asked to stand up and simulate descending stairs (protocol 2) while again the spectroscope measurements will be performed.

What are the possible benefits and risks of participating?
By participating in this study one can contribute to developing new insights into the bone blood perfusion and maybe change the way of thinking of best treatment strategies for this frequent and often long-standing painful condition. The Medical Ethics Committee concluded that the risks for participants are low to absent. This is due to the non-invasive character of the bone blood perfusion measurements.

Where is the study run from?
The study runs from the orthopedic surgery department of the Amsterdam Medical Centers in the Netherlands.

When is the study starting and how long is it expected to run for?
February 2021 to December 2022

Who is funding the study?
Investigator initiated and funded

Who is the main contact?
Martin Ophey, m.j.ophey@amsterdamumc.nl

Contact information

Mr Martin Ophey
Scientific

Meibergdreef 9
Amsterdam
1105AZ
Netherlands

ORCID ID	0000-0002-8674-0477
Phone	+31-650616509
Email	m.j.ophey@amsterdamumc.nl

Study information

Study design	Single-center single-blinded observational case-control study
Primary study design	Observational
Secondary study design	Case-control study
Study setting(s)	Other
Study type	Other
Participant information sheet	Not available in web format, please use contact details to request a participant information sheet.
Scientific title	Bone blood perfusion of the patella measured with non-invasive Near Infrared Spectroscopy in patients with patellofemoral pain
Study acronym	NIRSpatella
Study objectives	In patients with patellofemoral pain bone blood perfusion of the patella bone is reduced when compared to healthy controls.
Ethics approval(s)	Approved 15/11/2021, Medical Ethics Committee of the Amsterdam Medical Center (AMC, Meibergdreef 9, 1105AZ, Amsterdam, the Netherlands; +31(0)205669111; indienenmetc@amsterdamumc.nl), ref: 2021_088#B2021652
Health condition(s) or problem(s) studied	Patellofemoral pain in young adults
Intervention	Bone blood perfusion will be measured with non-invasive Near InfraRed Spectroscopy (NIRS). The measurements will take place in two different postures, which usually provoke symptoms of knee pain in patients with patellfemoral pain. The first posture is prolonged sitting with the knee bend for 30 minutes and the second posture mimics descending stairs on a decline step-down exercise.
Intervention type	Other
Primary outcome measure	Bone blood perfusion expressed as concentrations of oxygenated hemoglobin (O2Hb) and deoxygenated hemoglobin (HHb) measured using NIRS during the two conditions.
Secondary outcome measures	Measured at a single time point (baseline) unless otherwise stated: 1. Anterior Knee Pain Scale – Dutch Version (AKPS-DV), 13 item questionnaire 2. Tegner Score, 10 item level of physical activity 3. Blood pressure (mmHg), sphygmomanometer 4. Prepatellar skinfold thickness measured with Harpenden skinfold caliper 5. Patella width measured with caliper 6. Decline step-down test (DSDT) measuring pain-free flexion angle 7. Lower limb range of motion (LLROM) measuring soft tissue flexibility of the kinetic chain 8. Visual Analogue Scale (VAS) measuring pain intensity while performing protocol 1 and 2
Overall study start date	01/02/2021
Completion date	31/12/2022

Eligibility

Participant type(s)	Patient
Age group	Adult
Lower age limit	18 Years
Upper age limit	40 Years
Sex	Both
Target number of participants	90
Total final enrolment	60
Key inclusion criteria	1. Age 18-40 years 2. Diagnosis of patellofemoral pain for more than 3 months 3. No other specific knee conditions (ACL, meniscus, OA, jumpers knee) 4. Non-traumatic onset of PFP
Key exclusion criteria	1. PFP due to trauma or post-surgery 2. Other specific knee conditions (ACL, meniscus, OA, jumpers knee)
Date of first enrolment	01/02/2022
Date of final enrolment	10/05/2022

Locations

Countries of recruitment

Netherlands

Study participating centre

YsveldFysio

Nieuwstraat 9
Nijmegen
6511PT
Netherlands

Sponsor information

Amsterdam University Medical Centers
Hospital/treatment centre

Meijbergdreef 9
Amsterdam
1105AZ
Netherlands

Phone	+31(0)20 566 2551
Email	e.l.rolleman@amsterdamumc.nl
Website	https://www.amc.nl/web/specialismen/orthopedie.htm
"ROR"	https://ror.org/05grdyy37

Funders

Funder type

Other

Investigator initiated and funded

No information available

Results and Publications

Intention to publish date	31/12/2023
Individual participant data (IPD) Intention to share	Yes
IPD sharing plan summary	Published as a supplement to the results publication
Publication and dissemination plan	Planned publication of the protocol and the results of the study in an international well-known peer-reviewd journal.
IPD sharing plan	The datasets generated and/or analysed during the current study will be published as a supplement to the subsequent results publication.

Study outputs

Output type	Details	Date created	Date added	Peer reviewed?	Patient-facing?
Results article		29/11/2023	29/11/2023	Yes	No

Editorial Notes

29/11/2023: Publication reference added.
12/07/2023: The intention to publish date has been changed from 31/07/2023 to 31/12/2023.
23/03/2023: The intention to publish date has been changed from 01/03/2023 to 31/07/2023.
19/05/2022: The following changes have been made:
1. The recruitment end date has been changed from 01/10/2022 to 10/05/2022.
2. The total final enrolment number has been added.
24/01/2022: The sponsor contact email has been updated.
15/12/2021: Trial's existence confirmed by Amsterdam UMC.