The Effect of Blood Flow Restriction Method in Patellar Instability

December 19, 2025 updated by: Begum Kara Kaya, Biruni University

The Effect of Blood Flow Restriction Applied to the Extensor Muscles on Muscle Architecture and Strength, Knee Pain, and Functions in Minor Patellar Instability

The blood flow restriction method, the effects of which have been frequently investigated in the literature in recent years, can produce muscle hypertrophy with low-intensity load and can be easily tolerated through to low mechanical stress, seems to be an exercise approach that can be used in the recovery of strength in cases with minor patellar instability and can contribute to the recovery of functional capacity without delay.

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

Patellar instability is defined as disruption of normal movement of the patella in the trochlear groove, symptomatic, medial-lateral displacement. Patients with patellar instability may not be able to tolerate high-intensity quadriceps exercises in the early period of strengthening programs due to pain symptoms, and therefore strength recovery may be delayed. However, it is important to restore muscle strength, especially vastus medialis obliquus strength, as early as possible in patellar instability. The blood flow restriction method, the effects of which have been frequently investigated in the literature in recent years, can produce muscle hypertrophy with low-intensity load and can be easily tolerated through to low mechanical stress, seems to be an exercise approach that can be used in the recovery of strength in cases with minor patellar instability and can contribute to the recovery of functional capacity without delay.

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.
34

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.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

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

18 years to 40 years (Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Being between the ages of 18-40 years,
  • Volunteering to participate in the study,
  • Having a complaint of anterior knee pain for at least 3 months,
  • Having been diagnosed with unilateral minor patellar instability,
  • Absence of any other ongoing clinical problems that interfere with exercise (will be questioned by the Physical Activity Readiness Questionnaire for All).

Exclusion Criteria:

  • History of one or more traumatic-atraumatic patella dislocations,
  • Evidence of osteoarthritis on radiological imaging (≥ Kellgren-Lawrence Stage 2)
  • Having at least one of the contraindications preventing the application of blood flow restrictive exercises (Smoking, previous venous thromboembolism, risk of peripheral vascular disease (ankle-brachial index <0.9), coronary heart disease, hypertension, hemophilia, etc.),
  • Previously diagnosed cardiovascular disease limiting effort capacity (Myocardial infarction, angina, exercise intolerance, etc.),
  • Previously diagnosed neurological disorder or cognitive dysfunction (stroke, dementia, schizophrenia, etc.),
  • Orthopedic lower extremity surgery in the last 1 year,
  • Body mass index ≥ 30 kg/m2.

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: Treatment
  • 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: With Blood Flow Restriction
Other: Rehabilitation with blood blow restriction
The rehabilitation program will be applied 2 days a week, for total of 8 weeks.
Active Comparator: Without Blood Flow Restriction
Other: Rehabilitation without blood flow restriction
The rehabilitation program will be applied 2 days a week, for total of 8 weeks.

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
Assessment of Muscle Architecture and Hypertrophy
Time Frame: 8 weeks
A portable, diagnostic B-mode ultrasound device with a linear probe will be used to evaluate the quadriceps muscle architecture. Cross-sectional areas, muscle thicknesses, fascicle lengths, and pennation angles, the architectural parameters of both thigh muscles, will be assessed by ultrasound. All assessments will be calculated as millimeters.
8 weeks

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
Assessment of Muscle Strength
Time Frame: 8 weeks
The concentric and eccentric strength of the knee extensor muscle (quadriceps) and its antagonist (hamstring), will be measured using the isokinetic dynamometer.
8 weeks
Assessment of Pain
Time Frame: 8 weeks
Visual Analogue Scale (VAS) will be used to evaluate the severity of pain in the knee of patients during activity, at rest, and at night. In the evaluation of pain intensity with VAS, the patient is asked to mark his pain above the 10-centimeter line defined as "0-no pain" and "10 unbearable pain" at both ends.
8 weeks
Evaluation of Functions
Time Frame: 8 weeks
The Tampa Kinesiophobia Scale (TKS) will be used to evaluate kinesiophobia. The lower extremity functional capacity of the subjects will be evaluated with the 1-minute sit-to-stand test, and the knee functions will be evaluated with the Lysholm Knee Scoring Scale and the Kujala Patellofemoral Joint Evaluation Scale, which are patient-answered scales that are recommended to be used in cases with patellar instability. In addition, fatigue determination after each application will be made with the Borg CR-10 Perceived Fatigue Scale. Scales will be filled by the face-to-face evaluation method.
8 weeks
Evaluation of Satisfaction and Change
Time Frame: 8th week
General satisfaction and the change in clinical status perceived by the participants will be evaluated with the 7 points Global Rating of Change Scale after the rehabilitation program. According to the scale, it is expressed as "-3: I am much worse, -2: I am worse, -1: I am a little worse, 0: No change, 1: I am a little better, 2: I am better, 3: I am much better".
8th week

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.
Biruni University

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Ayşe Zengin Alpözgen, PhD, Istanbul University - Cerrahpasa

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.
January 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 30, 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).
July 26, 2022

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.
July 29, 2022

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.
August 2, 2022

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.
December 26, 2025

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.
December 19, 2025

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.
December 1, 2025

More Information

Terms related to this study

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.
  • PFI

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

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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