BFR Training and Knee Osteoarthritis

The Impact of Blood-flow-restricted Exercise Training and Pain Education on Pain, Function, Muscle Thickness, and Self-satisfaction in Patients With Knee Osteoarthritis.

Knee osteoarthritis (KOA) is a chronic, progressive degenerative joint disease characterized by cartilage and bone degeneration, synovial inflammation, and structural changes. Clinically, it presents with pain, morning stiffness, swelling, crepitus, and limited range of motion, leading to functional impairment, gait abnormalities, and reduced quality of life. Globally, KOA affects ~302 million people. In Saudi Arabia, prevalence rises from 30.8% (ages 46-55) to >60% (ages 66-75), with higher rates in older, female, and obese individuals. Key risk factors include aging, female sex, obesity, prior knee injury, and genetics. The condition imposes significant health burdens and socioeconomic costs.

The International Classification of Functioning, Disability, and Health (ICF) identifies KOA as a major cause of physical disability. Pain, restricted motion, and muscle weakness drive quality-of-life decline. While pharmacological treatments exist, physical therapy interventions (education, exercise, weight loss) are crucial, though their success depends on patient behavioral change.

Traditional biomedical education inadequately addresses chronic pain. Pain neuroscience education (PNE) teaches the biology and physiology of pain, supported by a biopsychosocial assessment. PNE is increasingly used by physiotherapists for chronic pain management.

Quadriceps weakness contributes to functional decline in KOA. Conventional high-load resistance training may exacerbate joint pain; thus, low- to moderate-intensity training is recommended. Blood flow restriction training (BFRT) partially restricts arterial inflow and occludes venous outflow during low-load exercise, originally developed as "kaatsu training" in Japan. BFRT is used in rehabilitation and performance training across healthy individuals, athletes, older adults, and hypertensive patients. Factors affecting adaptations include occlusion pressure, type (continuous/intermittent), exercise intensity, and volume. Low-load resistance with BFRT reduces joint pain and increases muscle strength and mass in older adults, including those with KOA risk factors.

A systematic review of six RCTs on BFRT in KOA patients showed significant pain improvement in four studies, but meta-analysis did not confirm a significant difference. Combining exercise therapy and education is recommended for musculoskeletal pain reduction; pain education alone reduced healthcare spending by 45% over three years. However, physical therapists underutilize pain management approaches, and knowledge gaps remain barriers.

Controlled clinical studies on BFRT in KOA are lacking. This randomized trial aims to evaluate whether BFRT, PNE, and standard treatment improve pain, function, muscle thickness, and patient satisfaction in KOA patients.

Study Overview

• Status: Not yet recruiting
• Conditions: Knee Osteoarthristis
• Intervention / Treatment: Other: Standard Treatment; Other: Pain neuroscience education; Other: Blood flow restriction training

Detailed Description

KOA is a chronic, progressive, and severe degenerative joint disease marked by the slow degeneration of articular cartilage and subchondral bone, synovial inflammation, and structural changes in the meniscus and ligaments. Clinically, it is characterized by chronic knee pain, morning stiffness, swelling, crepitus, and a restricted range of motion (ROM). These signs and symptoms frequently result in functional impairment, gait abnormalities, and a significant decline in quality of life.

KOA is a common degenerative disease characterized by joint swelling, discomfort, stiffness, functional impairments, severe muscle atrophy, and even incapacity. According to statistics, KOA affects an estimated 302 million people worldwide. In Saudi Arabia, the prevalence of knee osteoarthritis (KOA) rises from 30.8% in those aged 46-55 to over 60% in those aged 66-75. KOA is particularly common in older, female, and obese people. The condition is strongly correlated with high BMI, inactivity, and aging. It frequently results in severe discomfort and restricted movement.

This syndrome is becoming more prevalent as the population ages and physical fitness declines; it imposes a greater health burden on individuals and has a substantial impact on the healthcare system and socioeconomic expenditures.

According to the International Classification of Functioning, Disability, and Health (ICF), KOA leads to activity limitations and participation restrictions as well as impairment. It is one of the leading causes of physical disability among the general population. In addition to causing considerable impairment, this condition results in a notable decrease in quality of life due to pain, limited range of motion, and loss of muscle strength.The Key risk factors of KOA include aging, gender differences (women more than men), obesity, previous knee injuries, and genetic factors.

Besides pharmacological treatments, physical therapy intervention such as (education, exercise, and weight loss) are crucial for managing KOA subjects, The effectiveness of such treatments depends on the patient's willingness to change their behavior, which can be difficult to achieve.

Due to scientific advances in pain treatment and rising rates of chronic pain prevalence, the traditional biomedical educational model was unable to adequately address pain. In pain science education, the process of teaching the underlying biology and physiology of pain is known as pain neuroscience education (PNE).Physiotherapists increasingly use PNE in the treatment of chronic pain patients. PNE should be preceded by a comprehensive biopsychosocial assessment in order to evaluate pain neurophysiology and biopsychosocial interactions and give the patient a voice in this process.

Functional decline in KOA patients is associated with quadriceps weakness. In conventional interventions to strengthen muscles, high-load or high-intensity resistance training is commonly used. Adults with KOA are recommended to perform low- to moderate-intensity resistance training to improve muscle strength and limit joint pain.

Blood flow restriction training (BFRT) involves partially restricting arterial blood flow into muscles as well as occluding the venous outflow during exercise. It was first introduced into the literature by Japanese doctor called Yoshiaki Sato in Japan in 1987 who used tourniquet ischemia to induce muscle fatigue. This technique was originally called "kaatsu training," meaning "training with added pressure." Kaatsu training is now performed all over the world and is more commonly referred to as "BFRT" and achieved using a pneumatic tourniquet system.

In addition to physical rehabilitation, BFRT is used for physical training and performance in healthy individuals. There has been extensive research into its value as a training tool, including elite- and amateur-level athletes, untrained young and older adults, and hypertensive individuals.

There were different Factors affecting exercise adaptations with BFR including pressure of occlusion (partial or complete), type of occlusion (continuous or intermittent), intensity of exercise, and volume of exercise with BFR.

The combination of low-load resistance training with BFRT may help to reduce training related joint pain. In BFRT training, the exercising limb is compressed externally and blood flow is mildly restricted to the activated skeletal muscle. It has been independently validated that BFRT resistance training can increase skeletal muscle strength and mass in older adults, especially those with risk factors for knee osteoarthritis.

The results of Gama Linhares and colleague's systematic review, which was done on six RCTs included in this meta-analysis, four studies showed a significant improvement in pain with the use of the BFRT in KOA patients (p < 0.05). However, the results of the meta-analysis did not confirm this significant difference.

A combination of exercise therapy and education was recommended as the most effective intervention for reducing musculoskeletal pain. In addition, using pain education alone reduced health care spending by 45% over three years. Pain management approaches don't seem to be widely used by physical therapists in clinical settings. Moreover, pain management prescriptions are lacking in knowledge, making pain a bigger barrier in areas where knowledge is lacking. It is therefore important to emphasize the importance of education and effective therapeutic exercise(s).

To our knowledge, controlled clinical studies investigating the effect of BFRT in KOA subjects are currently lacking. Therefore, the current randomized trial aims to examine whether interventions of BFRT, PNE, with standard treatment can serve as an effective method for improving pain, function, muscle thickness, and patient satisfaction in patients with KOA.

• Study Type: Interventional
• Enrollment (Estimated): 90
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Hisham Hussein, PhD; Phone Number: +20543704108; Email: hm.hussein@uoh.edu.sa

Study Locations

• Saudi Arabia
  • Ha'il Region
    • Ha'il, Ha'il Region, Saudi Arabia, 3994
      • University of Hail
      • Contact: Hisham Hussein, PhD; Phone Number: 0543704108; Email: hm.hussein@uoh.edu.sa

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Male and female Age ≥ 40years.
• Clinical and radiographic diagnosis of unilateral knee osteoarthritis KOA (Kellgren-Lawrence grade 2, or 3).
• Willing to attend 3 supervised sessions/week for 8 weeks.
• Able to provide informed consent.

Exclusion Criteria:

• Peripheral vascular disease, active cancer, lower limb infection, open wound
• history of intra-articular injections within the last 3 months
• medical condition that may affect their ability to perform exercise (uncontrolled cardiovascular, or neurological disorders)
• cognitive and psychiatric disorders

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: control group; All participants will be received conventional TENS (Chattanooga, Intellect Advanced, USA) and exercises	Other: Standard Treatment; Physical Modalities (TENS, US, and superficial heat) All participants will be received conventional TENS (Chattanooga, Intellect Advanced, USA) with the following parameters: frequency, 100 Hz; pulse duration, 60 ms; amplitude-modulated frequency, 10%; and intensity adjusted to a comfortable tingling sensation. Two electrodes (single channel) were used: the first was placed over the ipsilateral lumbar region, and the second over the popliteal fossa. The duration of the TENS was 20 minutes.; Exercise trainingHamstrings stretching, 3 repetitions of 30 s ,Hip abduction with weights (side lying), 3 sets of 10 repetitions Hip abduction with weights (side lying), 3 sets of 10 repetitionsCalf raises, 3 sets of 10 repetitionsCalm exercises (side lying) with elastic band, 3 sets of 10 repetitions+Seated knee extension (machine), 90°-0° of knee flexion, 3 sets of 10 repetit; Other: Pain neuroscience education; Pain neuroscience education was used before in such cases (knee osteoarthritis). The PNE will include five dimensions with a focus on reducing fear-avoidance beliefs and catastrophic thoughts to promote self-efficacy. This educational session will be provided only by one therapist to all the participants. The session includes a verbal explanation with a visual presentation on PowerPoint with a duration of 30-45 minutes. Educational content of the session will include pictures, examples, and metaphors for explaining pain. The metaphorical alarm system will be used to describe the nervous system's sensitivity. The purpose of this session will be to establish rapport with the participants, highlight the maladaptive nature of chronic pain, emphasize the significance of pain's role in tissue protection, and improve the subjects' understanding of factors that influence pain production.; Other: Blood flow restriction training; For blood flow restriction, a 10 cm cuff (Theratool, China) will be placed around the most proximal portion of the exercising leg (around the bulk of the quadriceps). While the subject is seated on a chair, the pressure cuff will be inflated to 120 mmHg for 30 seconds, then deflated. The pressure cuff will then be inflated four more times, with each period increased by 20 mmHg. Each period lasted 30 seconds, and the cuff was released for 10 seconds between periods until a final pressure of 200 mmHg was reached. With the pressure maintained at 200 mmHg, the subjects then will perform a four set of leg extension exercises (75 repetitions across four sets of exercises, with 30 repetitions in the first set and 15 repetitions in each subsequent set) at the final exercise pressure, the exercise loads will be set between 20 and 40% of 1RM,for three time per week /8weeks
Experimental: Pain neuroscience education group; The PNE will include five dimensions with a focus on reducing fear-avoidance beliefs and catastrophic thoughts to promote self-efficacy. This educational session will be provided only by one therapist to all the participants. The session includes a verbal explanation with a visual presentation on PowerPoint with a duration of 30-45 minutes. Educational content of the session will include pictures, examples, and metaphors for explaining pain. The metaphorical alarm system will be used to describe the nervous system's sensitivity. plus the standard treatment given to the control group.	Other: Pain neuroscience education; Pain neuroscience education was used before in such cases (knee osteoarthritis). The PNE will include five dimensions with a focus on reducing fear-avoidance beliefs and catastrophic thoughts to promote self-efficacy. This educational session will be provided only by one therapist to all the participants. The session includes a verbal explanation with a visual presentation on PowerPoint with a duration of 30-45 minutes. Educational content of the session will include pictures, examples, and metaphors for explaining pain. The metaphorical alarm system will be used to describe the nervous system's sensitivity. The purpose of this session will be to establish rapport with the participants, highlight the maladaptive nature of chronic pain, emphasize the significance of pain's role in tissue protection, and improve the subjects' understanding of factors that influence pain production.
Experimental: Blood flow restriction training; The participant will receive the same intervention of control group in addition to Blood flow restriction training. For blood flow restriction, a 10 cm cuff (Theratool, China) will be placed around the most proximal portion of the exercising leg (around the bulk of the quadriceps). While the subject is seated on a chair, the pressure cuff will be inflated to 120 mmHg for 30 seconds, then deflated. The pressure cuff will then be inflated four more times, with each period increased by 20 mmHg. Each period lasted 30 seconds, and the cuff was released for 10 seconds between periods until a final pressure of 200 mmHg was reached. With the pressure maintained at 200 mmHg, the subjects then will perform a four set of leg extension exercises (75 repetitions across four sets of exercises, with 30 repetitions in the first set and 15 repetitions in each subsequent set) at the final exercise pressure, the exercise loads will be set between 20 and 40% of 1RM,for three time per week /8weeks	Other: Blood flow restriction training; For blood flow restriction, a 10 cm cuff (Theratool, China) will be placed around the most proximal portion of the exercising leg (around the bulk of the quadriceps). While the subject is seated on a chair, the pressure cuff will be inflated to 120 mmHg for 30 seconds, then deflated. The pressure cuff will then be inflated four more times, with each period increased by 20 mmHg. Each period lasted 30 seconds, and the cuff was released for 10 seconds between periods until a final pressure of 200 mmHg was reached. With the pressure maintained at 200 mmHg, the subjects then will perform a four set of leg extension exercises (75 repetitions across four sets of exercises, with 30 repetitions in the first set and 15 repetitions in each subsequent set) at the final exercise pressure, the exercise loads will be set between 20 and 40% of 1RM,for three time per week /8weeks

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pain by the numeric pain rating scale	The Numeric Pain Rating Scale (NPRS) is a unidimensional 0-to-10 measure, where 0 denotes "no pain" and 10 signifies "worst imaginable pain." Participants indicated their current pain intensity by choosing the number that best reflected their experience ,Previous investigations have confirmed the NPRS's strong psychometric properties, reporting validity and reliability coefficients of 0.941 and 0.95, respectively	at baseline, after 4 weeks of intervention program, and after 2 months follow up

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pain catastrophizing by Pain Catastrophizing Scale (PCS)	The Pain Catastrophizing Scale (PCS) is a 13-item self-report questionnaire used to measure the degree to which individuals both in clinical and research settings experience negative cognitive-emotional responses to actual or anticipated pain. It assesses three dimensions: rumination, magnification, and helplessness, The validity and reliability of the Arabic version of PCS has been previously confirmed	at baseline, after 4 weeks of interventions, and after 2 months follow up
Kinesiophobia by tampa scale of kinesiophobia	Kinesiophobia. Tampa Scale for Kinesiophobia (TSK) contains 17 items related to fear of movement and reinjury. The score ranges from 17 to 68 (scores ≤ 37 presenting low fear and scores > 37 presenting high fear of movement), The validty and reliability of the Arabic version of Kinesiophobia. Tampa Scale was confirmed.	at baseline, after 4 weeks of interventions, and after 2 months follow up
Muscle thickness (MT) measured by ultrasound	Muscle thickness will be assessed from images obtained in vivo at rest using B-mode ultrasonography. MT has previously been assessed by placing the ultrasound probe transversally in relation to the limb and evaluated as the perpendicular distance between the skeletal muscle interfaces. Longitudinal ultrasound scans (ie, with the probe aligned with the fascicle plane) have also been used to detect changes in muscle size and growth as well as skeletal muscle architecture.	at baseline, after 4 weeks of intervention, and after 2 months follow up
Knee Injury and Osteoarthritis Function	The Knee Injury and Osteoarthritis Outcome Score (KOOS) is a self-administered questionnaire designed to assess patients' opinions of their knee and related problems. It consists of 42 items categorized into five subscales: pain (9 items), symptoms (7 items), activities of daily living (17 items), sports (5 items), and quality of life (QoL) (4 items). Each item is rated from 0 (none) to 4 (extreme). Each subscale is assessed separately, ranging from 0 (extremely difficult) to 100 (optimal state)(40), The KOOS demonstrates reliability and validity for evaluating the course of knee injury and treatment outcomes. Scores are transformed to a 0-100 scale, with zero representing extreme knee problems and 100 representing no knee problems as common in orthopaedic scales and generic measures. Scores between 0 and 100 represent the percentage of total possible score achieved.	at baseline, after 4 weeks of intervention, and after 2 months follow up
Lower limb mobility by Time up and go test (TUG)	The 'timed up and go' test (TUG) is a simple, quick, and widely used clinical performance-based measure of lower extremity function, mobility, and fall risk among older adults. TUG is a valid and reliable test; subjects are asked to stand from a standard chair, walk a distance of 3 meters (marked on the floor) at a comfortable pace, turn, walk back, and sit down; all subjects are allowed to use routine walking aids, but are forbidden from using their arms to stand up, There is no physical assistance provided, A stopwatch is used to measure the time it takes to complete the task, Upon receiving the command 'go,' timing begins and stops when the subject's back is positioned against the back of the chair, The time needed to perform the task was recorded in seconds. Interpretation: < 10 seconds = normal, < 20 seconds = good mobility, can go out alone, mobile without a gait aid., < 30 seconds = problems, cannot go outside alone, requires a gait aid.	at baseline, after 4 weeks of interventions, and after 2 months follow up

Collaborators and Investigators

• Sponsor: University of Hail

Study record dates

Study Major Dates

• Study Start (Estimated): June 15, 2026
• Primary Completion (Estimated): December 30, 2026
• Study Completion (Estimated): December 30, 2026

Study Registration Dates

• First Submitted: May 9, 2026
• First Submitted That Met QC Criteria: May 9, 2026
• First Posted (Actual): May 15, 2026

Study Record Updates

• Last Update Posted (Actual): May 20, 2026
• Last Update Submitted That Met QC Criteria: May 17, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: osteoarthritis; blood flow restrriction; muscles; pain; function
• Additional Relevant MeSH Terms: Neurologic Manifestations; Musculoskeletal Diseases; Arthritis; Joint Diseases; Rheumatic Diseases; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Pain; Osteoarthritis; Therapeutics; Physical Therapy Modalities; Patient Care; Exercise Therapy; Rehabilitation; Aftercare; Continuity of Patient Care; Blood Flow Restriction Therapy
• Other Study ID Numbers: H-2026-143

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: will be used for other future research projects

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No