Different Levels of Blood Flow Restriction Versus Moderate Intensity Exercises in Patients With Knee Osteoarthritis

May 2, 2026 updated by: Farah Fouad Gomaa El Gamal, Cairo University

Blood Flow Restriction With Different Loads Versus Moderate Resistive Exercises in Patients With Knee Osteoarthritis: A Double Blinded Randomized Controlled Trial

This clinical trail will be conducted to investigate the effect of blood flow restriction (BFR) with different load levels between low blood occlusion percentage (50%) group and high blood occlusion percentage (70%) compared to moderate intensity training (60% of 1 RM) in patients with chronic knee osteoarthritis.

The main questions it aims to answer are:

  1. Will there be no difference between the effect of (70% vs 50%) of BFR versus traditional moderate resistive training exercises on pain intensity in knee osteoarthritis ?
  2. Will there be no difference between the effect of (70% vs 50%) of BFR versus traditional moderate resistive training exercises on quadriceps muscle strength in knee osteoarthritis ?
  3. Will there be no difference difference between the effect of (70% vs 50%) of BFR versus traditional moderate resistive training exercises on rate of perceived exertion in knee osteoarthritis ?
  4. Will there be no difference between the effect of (70% vs 50%) of BFR versus traditional moderate resistive training exercises on functional ability in knee osteoarthritis ?
  5. Will there be no difference between the effect of (70% vs 50%) of BFR versus traditional moderate resistive training exercises on physical function in knee osteoarthritis ?

All participants will receive:

  1. 16 sessions of supervised intervention 2 times per week for 8 weeks.
  2. The assessment will be at 3 time points, baseline and at 4 weeks and at 8 weeks.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not 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

Knee osteoarthritis (KOA) is a prevalent degenerative musculoskeletal condition that primarily causing pain, stiffness, and disability. It is a multifactorial disease influenced by a combination of genetic, biomechanical, and environmental factors Osteoarthritis Research Society International (ORSI) recommended strength training as a possible treatment method to slow progression of knee OA. Strength training, as recommended by the American College of Sports Medicine (ACSM), must be performed at a minimum resistance training load of 60% to 70% 1-repetition maximum (1RM) for strength improvement.

Only 13% of older patients with knee OA satisfactorily can perform moderate to vigorous physical activity.

Unfortunately, risk factors of knee OA (as obesity, knee pain, knee injury/surgery) also contribute to a perceived reduced tolerance to the resistive training programs recommended for eliciting strength gains.

An alternative to traditional strength training that may be well tolerated by patients with Knee OA is Blood flow restriction (BFR) training.

This reduced blood flow creates a unique physiological environment, inducing a state of metabolic stress and cellular hypoxia in the muscles.

Although the advantages of BFRT in musculoskeletal rehabilitation that reported in the literature, there are conflicting results compared to traditional exercises, as the different protocols parameters, exercises, high risk of bias across previous studies contribute to different conclusions.

Consequently, it raises the question if BFR without exercises can be effective in comparison with traditional exercises that focus on having an efficient intensity to produce muscle strength gain.

Yet, up to authors knowledge, no study has assessed whether BFR at rest could also promote similar gains in muscle strength for the knee OA treatment, which theoretically would increase patient's adherence to KOA treatment based on conclusions of systemic review of BFR without exercises for immobilized patients after orthopedic surgery (Cerqueira et al., 2019).

Another relevant issue is the proper blood flow restriction level for optimal results. Thus, pushes the need for determining a pressure load with the least adverse effects.

Therefore, the main purpose of this study is to assess different protocols of BFR without additional exercises compared to MI-RT for pain reduction in patients with KOA. The secondary purpose is to compare two load levels (70% vs 50%) of BFRT regarding pain, quadriceps muscle strength, rate of perceived exertion, self reported physical function, and functional ability.

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.
75

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 Locations

  • Egypt
    • Giza Governorate
      • Cairo, Giza Governorate, Egypt, 12611
        • CairoU

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

No

Description

Inclusion Criteria:

  • Patients diagnosed with chronic knee osteoarthritis referred by orthopedic surgeons participants of both genders age are 40-65.
  • Patients with grade 2 and 3 OA of the knee, according to radiologic evaluation
  • If both knees diagnosed as OA, the most affected one will be selected.
  • Diagnosis of Knee OA who had knee pain and functional disabilities for at least three months, according to American College of Rheumatology classification at screening visit.
  • Visual Analogue Scale (VAS) at rest score of ≥40 mm.
  • Arabic version of the western WOMAC (ArWOMAC) scores (average 37).
  • Moderate Physical activity score on the IPAQ (between 3.0 and 7.9 METS).

Exclusion Criteria:

  • Moderate to significant knee synovitis
  • Hot or red knee
  • History and/or physical examination findings compatible with the internal derangement of knee.
  • Knee pain that is initiated or increased with knee activity/exercise and finished or decreased with knee resting.
  • Other muscular, articular, or neurological condition affecting lower limb function.
  • Patients with any previous knee surgeries or fractures of lower limb
  • Patients who had undergone arthroscopy or treatment with intra-articular hyaluronic acid during the previous 6 months.
  • Psychological or psychiatric disorders that may affect a subject's participation in the study.
  • Participants with congenital musculoskeletal lower limb deformity.
  • Participated in other intervention studies on the past 6 months to screening
  • Participants with contraindications to blood flow Restriction Training.

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: Non-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: 50% Blood Flow Restriction Group

The Blood Flow Restriction device will be set to restrict blood flow at level of 50% of arterial occlusion pressure at rest.

Blood Flow Restriction sessions will be 5 sets of 5 mins of occlusion and 3 mins of free flow , 2 sessions per week for eight weeks exercises to assess its effects on knee osteoarthritis-related outcomes.
Device: Blood Flow Restriction Therapy Device

Blood Flow Restriction (BFR) therapy involves units use standardized cuffs of varying widths and lengths which are physically attached to the devices and provide the capability of precisely controlling the amount of pressure applied to each limb during exercise or at rest.

We will be using Smart Cuffs® 4.0 which allows for a fast, hassle-free personalized pressure calculation. With the built-in pressure sensor and on-board computer, it will calculate and set the optimal pressure for each participant's limb. There is no need for an external doppler probe or hand pump. Made in the USA, SmartCuffs® are registered with the FDA as a Class 1 Medical Device.

Blood flow restriction therapy is commonly paired with resistive training, so this study will explore the effect of blood flow restriction at rest for patients with osteoarthritis at different restriction levels (50% for first group and 70% for second group).

Other Names:
  • Smart cuffs 4.0
Experimental: 70% Blood Flow Restriction Group

The Blood Flow Restriction device will be set to restrict blood flow at level of 70% of arterial occlusion pressure at rest.

Blood Flow Restriction sessions will be 5 sets of 5 mins of occlusion and 3 mins of free flow , 2 sessions per week for eight weeks exercises to assess its effects on knee osteoarthritis-related outcomes.
Device: Blood Flow Restriction Therapy Device

Blood Flow Restriction (BFR) therapy involves units use standardized cuffs of varying widths and lengths which are physically attached to the devices and provide the capability of precisely controlling the amount of pressure applied to each limb during exercise or at rest.

We will be using Smart Cuffs® 4.0 which allows for a fast, hassle-free personalized pressure calculation. With the built-in pressure sensor and on-board computer, it will calculate and set the optimal pressure for each participant's limb. There is no need for an external doppler probe or hand pump. Made in the USA, SmartCuffs® are registered with the FDA as a Class 1 Medical Device.

Blood flow restriction therapy is commonly paired with resistive training, so this study will explore the effect of blood flow restriction at rest for patients with osteoarthritis at different restriction levels (50% for first group and 70% for second group).

Other Names:
  • Smart cuffs 4.0
Active Comparator: Moderate Intensity Exercise training Group

Patients assigned to this group will receive strengthening of the lower limb musculature through moderate intensity resistance training (60% of 1RM) for a total of 16 treatment sessions according to exercise guidelines for seniors with OA.

MIRT protocols consists of 3 sets for every exercise, 12 repetitions per set, rest period between sets 2 mins, 2 session per week for 8 weeks.

Resistance exercises will be performed using a 45° leg-press machine, 90°-0° of knee flexion knee extension machine, leg curl machine and calf raise machine.
Device: 45° leg-press machine, 90°-0° of knee flexion knee extension machine, leg curl machine and calf raise machine.
Patients assigned to group will receive strengthening of the lower limb musculature through moderate intensity resistance training (60% of 1RM) using a 45° leg-press machine, 90°-0° of knee flexion knee extension machine, leg curl machine and calf raise machine.

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
Change in pain intensity
Time Frame: Measured 3 times at basline, 4 weeks and 8 weeks

Measured by the Visual Analog Scale (VAS)which is a pain intensity assessment tool.

  • Represented with a 10 cm line with 0 indicating no pain and on the other end 10 indicating severe pain.
  • The patient is asked to move a marker on the line to the position which best describes their pain.
  • That it will serve as a subjective measure of their current level of knee pain intensity.

The closer the mark to zero is better.
Measured 3 times at basline, 4 weeks and 8 weeks
Measure change in quadriceps muscle strength
Time Frame: Measured 3 times at baseline, 4 weeks and 8 weeks

Hand-held dynamometer (HHD) will be used to measure the strength in quadriceps muscle.

  • The maximum force or pressure exerted by the quadriceps muscle during the contraction will be recorded.
  • Typically, this measurement is expressed in kilograms (kg) and then transferred to Newtons (N)
  • To enhance reliability, 3 trials may be conducted, and average will be taken to obtain a more representative measurement of muscle strength.
  • The higher the measurement the higher the muscle strength.
Measured 3 times at baseline, 4 weeks and 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
Change in functional ability
Time Frame: Measured 3 times at baseline, 4 weeks and 8 weeks

Measured by Timed Up and Go Test (TUG) to assess participants' mobility, balance, and functional performance.

  • The time taken by the patient to complete the entire sequence from rising from the chair to returning to a seated position will be measured.
  • This time will be recorded in seconds, representing the TUG test score.
  • 3 times will be conducted to ensure the accuracy of the TUG test score.
  • The average time from these trials will be calculated for a more reliable result.
  • High Risk of fall (>13.5 seconds)
  • None/low/moderate (<13.5 seconds) The lower the number the better as it represents better mobility, balance and functional performance.
Measured 3 times at baseline, 4 weeks and 8 weeks
Change in physical function levels
Time Frame: Measured 3 times at baseline, 4 weeks and 8 weeks

Measured by Arabic version of Western Ontario McMaster Universities Osteoarthritis Index for Knee Function (ArWOMAC).

The WOMAC questionnaire will be handed out to the participants. They will be informed that it consists of a series of questions related to their knee symptoms and how these symptoms affect their daily activities.

WOMAC is assigned a numerical score of 0-4 corresponding to severity (none, mild, moderate, severe, and extreme). The minimum score is 0, and the maximum score is 96 (20 points for pain, 8 points for joint stiffness, and 68 points for physical function).

The lower the score the better.
Measured 3 times at baseline, 4 weeks and 8 weeks
Change in Rate of perceived exertion scale (RPE)
Time Frame: Measured 3 times at basline , 4 weeks and 8 weeks

Measured by Arabic version of Omnibus Resistance Exercise 0-10 (OMNI-RES) as a scale for measuring an individual's effort and exertion, breathlessness and fatigue during physical work.

  • The OMNI Picture System is a collection of category scales used for rating of perceived exertion (RPE) as the subjective intensity of a person's feelings of effort, strain, discomfort, and/or fatigue when engaged in exercise or other physical activities.
  • With OMNI exertion scales, users select a number from 0 to 10 that best corresponds to their perceived intensity of physical exertion.
  • 0 represents extremely easy and 10 represents extremely hard.
  • The lower the number the better.
Measured 3 times at basline , 4 weeks and 8 weeks

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.
Cairo 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: Lecturer, Cairo University

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 (Actual)

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.
October 15, 2024

Primary Completion (Actual)

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.
February 26, 2025

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.
May 6, 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).
September 24, 2024

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.
October 9, 2024

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.
October 15, 2024

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.
May 6, 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.
May 2, 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.
September 1, 2025

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.
  • P.T.REC/012/005029

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

  • The risk that sharing prevents the exploitation of the entire potential of the data obtained.
  • Possible failures in patients' privacy protection.
  • Technical barriers such as the lack of standard formats and possible data misinterpretation.
  • Issues regarding data ownership.
  • Reuse of data for unfair commercial purposes.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

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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