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Osteoarthritis, KneeNCT05437770

Effects of Blood-flow Restricted Exercise Compared to Standard Rehabilitation in Patients With Knee Osteoarthritis

A study testing BFR (Blood-Flow Restricted exercise) and Standard rehabilitation in people with Osteoarthritis, Knee, run by Bispebjerg Hospital at 1 site in Denmark.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

The purpose of this study is to investigate the effect of low-intensity BFR exercise on joint pain, muscle mass, and mechanical muscle function compared to standard rehabilitering in adults with knee-OA. Read more about this study

Who is it for?
Any age
Conditions the study is for
Osteoarthritis, Knee
What is being tested?
BFR (Blood-Flow Restricted exercise) and Standard rehabilitation
Could I receive a placebo?
No, everyone receives an active treatment
How many people
96 participants
Where
1 siteDenmark
Study dates
1 Jan 2022to 14 Feb 2025
Phase
Interventional
Are there results?
None posted in the registry

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 Any age
  • All sexes
  • No healthy volunteers
  • Child, Adult, Older adult

Who may be able to join

  • All participants must meet the American College of Rheumatology (ACR) criteria for OA 35.
  • Visible OA on X-ray pictures (Kellgren \& Lawrence grade 2-3).
  • Unilateral pain and functional limitation for a minimum of 3 months.
  • Be able to voluntarily (i.e. unassisted) perform a 90 degrees flexion in the knee.
  • Be able to perform the machine exercise (knee extension) planned for the BFR training.
  • Danish-speaking.
  • No longer travel planned within the intervention period.

Who cannot join

  • Kellgren \& Lawrence grade 4.
  • Bilateral OA-symptoms.
  • Prior knee- or hip alloplasty.
  • Glucocorticosteroid injection in the knee within the last 6 months.
  • Inflammatory arthritis.
  • Known neurotic disease such as multiple sclerosis or peripheral neuropathy.
Show all 14Show fewer
  • Prior myocardial infarct or apoplexy, or chest pain during physical activity.
  • Other health related or medical conditions which makes it impossible participate in the study.
  • Furthermore, it is an exclusion criterium in the following conditions where use of pneumatic occlusion would be considered contraindicated:
  • Peripheral vascular disease
  • Excessive varicose veins
  • Prior history of deep venous thrombosis
  • Venous insufficiency causing edema in the lower legs
  • Systolic blood pressure over 160 mmHg or under 100 mmHg

Trial locations and contacts

1 site in 1 country.

Denmark1 site

  • Department of Physical and Occupational Therapy / Institute of Sports Medicine Copenhagen, Bispebjerg Hospital

    Copenhagen, 2400

Other trials in Denmark

About this study

Official title: Effects of Low-intensity Blood-flow Restricted Exercise Compared to Standard Rehabilitation in Patients With Knee Osteoarthritis - a Randomized Controlled Trial

The purpose of this study is to investigate the effect of low-intensity BFR exercise on joint pain, muscle mass, and mechanical muscle function compared to standard rehabilitering in adults with knee-OA.

Read the detailed description

Osteoarthritis (OA) is a common disease in Denmark with high socioeconomical costs. Representing the most widespread non-medical and non-operative treatment modality both internationally and in Denmark, knee-OA patients often are offered a combination of patient education, weight loss counseling and physical exercise. In Denmark the GLA:D (Good Life with osteoArthritis in Denmark) concept is a nationwide training paradigm which is a combination of education and supervised neuromuscular exercise (NEMEX). Physical exercise including conventional strength training has shown positive results on OA, however a large proportion of OA-patients are forced to refrain from this type of training to excessive joint- and muscle pain during and following the training sessions.

A more joint protecting type of training (BFR = Blood-Flow Restricted exercise), which are performed using low training load (<30% of maximum load) and with a reduced blood flow to the working muscles, has shown similar results to conventional heavy strength training. Based on these observations BFR exercise seems to represent an attractive training modality in patients with knee-OA.

The aim of the present study is to investigate the effect of low-intensity BFR exercise on joint pain, muscle mass, and mechanical muscle function compared to SR in adults with knee-OA. A second aim is to investigate if 12 weeks of training is more efficient compared to 8 weeks of training.

Patients diagnosed with knee-OA are eligible to participate. Inclusion takes place via the Institute of Sportsmedicine (ISMC), and the Department of Physical and Occupational Therapy at Bispebjerg Hospital. Patients will be called in for a preparatory examination by one of the attending physicians. At the consultation a standard clinical assessment will be performed and the participant will be examined for meeting the explicit inclusion or exclusion criteria of the study. If the participant after receiving all oral and written information wishes to participate in the study, an informed consent will be obtained. Randomization procedures will be performed. A randomized controlled trial design with two groups; 1) BFR, and 2) Standard rehabilitation. A total sample size of 95 participants are needed when assuming a 20 % dropout.

The intervention period will last 12 consecutive weeks with 2 weekly training sessions at several chosen physiotherapy clinics (standard rehabilitation) and at Bispebjerg Hospital (BFR). Participants in the standard rehabilitation group will be offered participation in the GLA:D programme supervised by GLA:D certified physiotherapists. The BFR group will be trained by instructors who are experienced in BFR exercise. Testing will take place before the intervention period, after 8 weeks of training and at the end of the intervention (12 weeks) except for the muscle biopsies which will take place before the intervention period and at the end (12 weeks). Patient-reported questionnaires will furthermore be assessed 6 months after the intervention period. Patients will be tested at Bispebjerg Hospital for a number of different outcome measures including joint- and muscle pain, functional level and mechanical muscle function (strength and muscle mass).

Being tested
BFR (Blood-Flow Restricted exercise), Standard rehabilitation
Keywords
Osteoarthritis, Blood-flow restriction, Exercise
Medical subject headings
Osteoarthritis, Knee, Osteoarthritis, Motor Activity

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • BFR (Blood-Flow Restricted exercise)Other

    The BFR group performs unilateral training with the knee-OA diagnosed leg first. BFR exercise is performed with a pneumatic cuff placed at the top of the thigh on the leg being trained. The cuff will be inflated to 60-80 % of the total arterial occlusion pressure (AOP). The participant will afterwards perform training of the knee extensors in a leg press exercise machine and a leg extension exercise machine with a load corresponding to 30 % of the maximal load (1RM = Repetition Maximum).

  • Standard rehabilitationOther

    The GLA:D programme involves a circuit training program with four stations. Each station involves two to six exercises where the participants perform 10-15 repetitions over 2-3 sets, which depends on the participants pain- and functional level. Following the 8 weeks GLA:D programme, participants will continue 4 weeks of team group training performing similar neuromuscular lower limb exercises as for the first 8 weeks.

Study groups in NCT05437770
Study groupRoleWhat they receive
BFR (Blood-Flow Restricted exercise)ExperimentalThe BFR training intervention group will perform low load blood-flow restricted exercise. Training twice a week for 12 weeks. The group will also attend a two hours education lecture with osteoarthritis information.
Receives: Other: BFR (Blood-Flow Restricted exercise)
Standard rehabilitationActive comparatorThe standard rehabilitation group will be offered participation in the Good Life with osteoArthritis in Denmark programme (GLA:D). The programme includes supervised team group training twice a week for 8 weeks and an education lecture. The GLA:D programme will be followed by 4 weeks of team group training continuing the exercises from the GLA:D programme.
Receives: Other: Standard rehabilitation

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Knee injury and Osteoarthritis Outcome Score (KOOS) - Pain subscale

    KOOS is a patient reported outcome instrument to assess the patient's opinion about their knee and associated problems. KOOS consists of 5 subscales; Pain, other Symptoms, Function in daily living (ADL), Function in sport and recreation (Sport/Rec) and knee related Quality of life (QOL). Primary outcome will be an assessment of the Pain subscale as a total KOOS score has not been validated. A normalized score for the entire subscale will be calculated and reported, ranging from zero (extreme symptoms) to 100 (no symptoms).

    Measured: Baseline (0 weeks)

  2. Knee injury and Osteoarthritis Outcome Score (KOOS) - Pain subscale

    KOOS is a patient reported outcome instrument to assess the patient's opinion about their knee and associated problems. KOOS consists of 5 subscales; Pain, other Symptoms, Function in daily living (ADL), Function in sport and recreation (Sport/Rec) and knee related Quality of life (QOL). Primary outcome will be an assessment of the Pain subscale as a total KOOS score has not been validated. A normalized score for the entire subscale will be calculated and reported, ranging from zero (extreme symptoms) to 100 (no symptoms).

    Measured: 8 weeks of training.

  3. Knee injury and Osteoarthritis Outcome Score (KOOS) - Pain subscale

    KOOS is a patient reported outcome instrument to assess the patient's opinion about their knee and associated problems. KOOS consists of 5 subscales; Pain, other Symptoms, Function in daily living (ADL), Function in sport and recreation (Sport/Rec) and knee related Quality of life (QOL). Primary outcome will be an assessment of the Pain subscale as a total KOOS score has not been validated. A normalized score for the entire subscale will be calculated and reported, ranging from zero (extreme symptoms) to 100 (no symptoms).

    Measured: 12 weeks of training.

  4. Knee injury and Osteoarthritis Outcome Score (KOOS) - Pain subscale

    KOOS is a patient reported outcome instrument to assess the patient's opinion about their knee and associated problems. KOOS consists of 5 subscales; Pain, other Symptoms, Function in daily living (ADL), Function in sport and recreation (Sport/Rec) and knee related Quality of life (QOL). Primary outcome will be an assessment of the Pain subscale as a total KOOS score has not been validated. A normalized score for the entire subscale will be calculated and reported, ranging from zero (extreme symptoms) to 100 (no symptoms).

    Measured: 6 months after the training intervention period.

Secondary outcomes (13)

  1. Myofiber Cross-Sectional Area (CSA)

    Quadriceps myofiber cross-sectional area will be measured using a GE Logiq E10 Logic View ultrasound to generate panoramic CSA images. Orientated in the axial-plane, the ultrasound probe is positioned perpendicularly, and a water-based gel is used to promote acoustic contact between the skin and the probe. The probe is moved manually with a slow and continuous movement from the lateral to the medial part of quadriceps along a marked line on the skin. The anatomical site for all measurements will be at 50% of the distance between the lateral condyle and greater trochanter of the femur.

    Measured: Baseline (0 weeks), 8 weeks and 12 weeks (the end of the intervention period)

  2. Pain Pressure Threshold (PPT)

    PPT is measured by a handheld pain pressure algometer at three different locations bilaterally. Most painful area in the medial joint line, tibialis anterior, and the muscle belly of extensor carpi radialis.

    Measured: Baseline (0 weeks), 8 weeks and 12 weeks (the end of the intervention period)

  3. Maximal Voluntary Isometric Contraction (MVIC)

    MVIC of the knee extensors is obtained during static knee extension in a KinCom, isokinetic dynamometer, at a knee joint angle of 70 degrees (0 degrees = full knee extension).

    Measured: Baseline (0 weeks), 8 weeks and 12 weeks (the end of the intervention period)

  4. Rate of Force Development (RFD)

    RFD of the knee extensors is obtained during static knee extension in a KinCom, isokinetic dynamometer, at a knee joint angle of 70 degrees (0 degrees = full knee extension).

    Measured: Baseline (0 weeks), 8 weeks and 12 weeks (the end of the intervention period)

  5. 4x10m Fast-Paced Walk Test (40m-FWT)

    The 40m-FWT is a test of walking speed over short distances and changing direction during walking. It measures the total time it takes to walk 4 * 10 m excluding turns (m/s).

    Measured: At baseline (0 weeks), 8 weeks, 12 weeks (the end of the intervention period)

  6. 30-second Chair Stand Test (30-s CST)

    The 30-s CST is used for testing leg strength and endurance. The 30-s CST will be assessed using a chair (seat height: 43-44 cm) with armrests. The 30-s CST measures the number of sit-to-stand repetitions completed within 30-s.

    Measured: At baseline (0 weeks), 8 weeks, 12 weeks (the end of the intervention period).

  7. Stair Climb Test (SCT)

    The SCT involves ascending and descending 10 stairs measuring 18 cm rise / 92 cm width. Each participant is asked to ascend/descend the stairs at their ''natural'' pace (without resting). One trial to ascend and descend is timed and recorded electronically.

    Measured: At baseline (0 weeks), 8 weeks, 12 weeks (the end of the intervention period).

  8. Myocellular component (Stem cells) assessed using muscle biopsies

    Muscle biopsies will be obtained for determination of important myocellular components (number of muscular stem cells). It will be assessed by obtaining needle biopsies (100-150 mg). The biopsies will be obtained unilaterally from the middle portion of the vastus lateralis muscle using the percutaneous needle biopsy technique of Bergström.

    Measured: Baseline (0 weeks) and 12 weeks (the end of the intervention period)

  9. Myocellular component (Fiber area) assessed using muscle biopsies

    Muscle biopsies will be obtained for determination of important myocellular components (fiber area in diameter: μm2). It will be assessed by obtaining needle biopsies (100-150 mg). The biopsies will be obtained unilaterally from the middle portion of the vastus lateralis muscle using the percutaneous needle biopsy technique of Bergström.

    Measured: Baseline (0 weeks) and 12 weeks (the end of the intervention period)

  10. Myocellular component (Myonuclei) assessed using muscle biopsies

    Muscle biopsies will be obtained for determination of important myocellular components (number of myonuclei). It will be assessed by obtaining needle biopsies (100-150 mg). The biopsies will be obtained unilaterally from the middle portion of the vastus lateralis muscle using the percutaneous needle biopsy technique of Bergström.

    Measured: Baseline (0 weeks) and 12 weeks (the end of the intervention period)

  11. Maximal lower limb muscle power

    Explosive lower limb muscle power will be assessed during a single-legged extensor power-rig. Subjects will be seated in the power-rig chair and pushes away the footplate connected to a flywheel as hard and fast as possible.

    Measured: Baseline (0 weeks), 8 weeks and 12 weeks (the end of the intervention period)

  12. Knee injury and Osteoarthritis Outcome Score (KOOS)

    KOOS is a patient reported outcome instrument to assess the patient's opinion about their knee and associated problems. KOOS consists of 5 subscales; Pain, other Symptoms, Function in daily living (ADL), Function in sport and recreation (Sport/Rec) and knee related Quality of life (QOL). A normalized score for the total KOOS score will be calculated and reported, ranging from zero (extreme symptoms) to 100 (no symptoms).

    Measured: At baseline (0 weeks), 8 weeks, 12 weeks (the end of the intervention period) and 6 months after the intervention period.

  13. Oxford Knee Score

    The Oxford Knee Score is a patient reported outcome measure that consists of 12 questions about an individual's level of function, activities of daily living and how they have been affected by pain over the preceding four weeks. Each question is scored from 0-4 where four is the best outcome and total scores range from 0 (poorest function) to 48 (maximal function).

    Measured: At baseline (0 weeks), 8 weeks, 12 weeks (the end of the intervention period) and 6 months after the intervention period.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted29 Jun 2022
  2. Study start1 Jan 2022
  3. Primary completion15 Jan 2025
  4. Study completion14 Feb 2025

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
Single blind
Who is masked
Outcomes assessor
Enrolment
96 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05437770
Sponsor's protocol ID
BRS-090288
Status last verified
Jun 2025
First submitted
11 Jun 2022
Last updated
29 Jun 2025
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Publications

  • Silverwood V, Blagojevic-Bucknall M, Jinks C, Jordan JL, Protheroe J, Jordan KP. Current evidence on risk factors for knee osteoarthritis in older adults: a systematic review and meta-analysis. Osteoarthritis Cartilage. 2015 Apr;23(4):507-15. doi: 10.1016/j.joca.2014.11.019. Epub 2014 Nov 29.

    PubMed 25447976

  • McAlindon TE, Bannuru RR, Sullivan MC, Arden NK, Berenbaum F, Bierma-Zeinstra SM, Hawker GA, Henrotin Y, Hunter DJ, Kawaguchi H, Kwoh K, Lohmander S, Rannou F, Roos EM, Underwood M. OARSI guidelines for the non-surgical management of knee osteoarthritis. Osteoarthritis Cartilage. 2014 Mar;22(3):363-88. doi: 10.1016/j.joca.2014.01.003. Epub 2014 Jan 24.

    PubMed 24462672

  • Ageberg E, Link A, Roos EM. Feasibility of neuromuscular training in patients with severe hip or knee OA: the individualized goal-based NEMEX-TJR training program. BMC Musculoskelet Disord. 2010 Jun 17;11:126. doi: 10.1186/1471-2474-11-126.

    PubMed 20565735

  • Dantas LO, Salvini TF, McAlindon TE. Knee osteoarthritis: key treatments and implications for physical therapy. Braz J Phys Ther. 2021 Mar-Apr;25(2):135-146. doi: 10.1016/j.bjpt.2020.08.004. Epub 2020 Sep 8.

    PubMed 33262080

  • Fransen M, McConnell S, Harmer AR, Van der Esch M, Simic M, Bennell KL. Exercise for osteoarthritis of the knee: a Cochrane systematic review. Br J Sports Med. 2015 Dec;49(24):1554-7. doi: 10.1136/bjsports-2015-095424. Epub 2015 Sep 24.

    PubMed 26405113

  • Holm PM, Schroder HM, Wernbom M, Skou ST. Low-dose strength training in addition to neuromuscular exercise and education in patients with knee osteoarthritis in secondary care - a randomized controlled trial. Osteoarthritis Cartilage. 2020 Jun;28(6):744-754. doi: 10.1016/j.joca.2020.02.839. Epub 2020 Mar 13.

    PubMed 32179197

  • Skou ST, Rasmussen S, Laursen MB, Rathleff MS, Arendt-Nielsen L, Simonsen O, Roos EM. The efficacy of 12 weeks non-surgical treatment for patients not eligible for total knee replacement: a randomized controlled trial with 1-year follow-up. Osteoarthritis Cartilage. 2015 Sep;23(9):1465-75. doi: 10.1016/j.joca.2015.04.021. Epub 2015 Apr 30.

    PubMed 25937024

  • Villadsen A, Overgaard S, Holsgaard-Larsen A, Christensen R, Roos EM. Immediate efficacy of neuromuscular exercise in patients with severe osteoarthritis of the hip or knee: a secondary analysis from a randomized controlled trial. J Rheumatol. 2014 Jul;41(7):1385-94. doi: 10.3899/jrheum.130642. Epub 2014 Jun 15.

    PubMed 24931956

  • Roos EM, Gronne DT, Skou ST, Zywiel MG, McGlasson R, Barton CJ, Kemp JL, Crossley KM, Davis AM. Immediate outcomes following the GLA:D(R) program in Denmark, Canada and Australia. A longitudinal analysis including 28,370 patients with symptomatic knee or hip osteoarthritis. Osteoarthritis Cartilage. 2021 Apr;29(4):502-506. doi: 10.1016/j.joca.2020.12.024. Epub 2021 Feb 6.

    PubMed 33561542

  • Skou ST, Odgaard A, Rasmussen JO, Roos EM. Group education and exercise is feasible in knee and hip osteoarthritis. Dan Med J. 2012 Dec;59(12):A4554.

    PubMed 23290290

  • Skou ST, Roos EM. Good Life with osteoArthritis in Denmark (GLA:D): evidence-based education and supervised neuromuscular exercise delivered by certified physiotherapists nationwide. BMC Musculoskelet Disord. 2017 Feb 7;18(1):72. doi: 10.1186/s12891-017-1439-y.

    PubMed 28173795

  • Bennell KL, Hunt MA, Wrigley TV, Lim BW, Hinman RS. Role of muscle in the genesis and management of knee osteoarthritis. Rheum Dis Clin North Am. 2008 Aug;34(3):731-54. doi: 10.1016/j.rdc.2008.05.005.

    PubMed 18687280

  • Skoffer B, Dalgas U, Mechlenburg I, Soballe K, Maribo T. Functional performance is associated with both knee extensor and flexor muscle strength in patients scheduled for total knee arthroplasty: A cross-sectional study. J Rehabil Med. 2015 May;47(5):454-9. doi: 10.2340/16501977-1940.

    PubMed 25678417

  • Bryk FF, Dos Reis AC, Fingerhut D, Araujo T, Schutzer M, Cury Rde P, Duarte A Jr, Fukuda TY. Exercises with partial vascular occlusion in patients with knee osteoarthritis: a randomized clinical trial. Knee Surg Sports Traumatol Arthrosc. 2016 May;24(5):1580-6. doi: 10.1007/s00167-016-4064-7. Epub 2016 Mar 12.

    PubMed 26971109

  • Ferraz RB, Gualano B, Rodrigues R, Kurimori CO, Fuller R, Lima FR, DE Sa-Pinto AL, Roschel H. Benefits of Resistance Training with Blood Flow Restriction in Knee Osteoarthritis. Med Sci Sports Exerc. 2018 May;50(5):897-905. doi: 10.1249/MSS.0000000000001530.

    PubMed 29266093

Questions about this trial

What is this clinical trial studying?

A study testing BFR (Blood-Flow Restricted exercise) and Standard rehabilitation in people with Osteoarthritis, Knee, run by Bispebjerg Hospital at 1 site in Denmark.

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 7 inclusion and 14 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: finished, as of the sponsor's last update on 29 Jun 2025. 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 Denmark. 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?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Knee injury and Osteoarthritis Outcome Score (KOOS) - Pain subscale (time frame: Baseline (0 weeks)). The study lists 4 primary outcomes in all. 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 NCT05437770, which also lists 59 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 29 Jun 2025.

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