Patellofemoral Pain SyndromeNCT05617911
Clinical Comparison of Patellofemoral Pain Syndrome Outcomes After Blood Flow Restriction Therapy
A study testing Blood Flow Restriction Cuff in people with Patellofemoral Pain Syndrome and Anterior Knee Pain Syndrome, run by Gaylord Hospital, Inc at 6 sites in United States.
Trial summary
The purpose of this study is to determine if Blood Flow Restriction therapy improves patient related outcomes in those diagnosed with Patellofemoral Pain Syndrome compared to those in the sham comparator control group. Read more about this study
- Who is it for?
- Ages 15 years and older
- Conditions the study is for
- Patellofemoral Pain Syndrome, Anterior Knee Pain Syndrome
- What is being tested?
- Blood Flow Restriction Cuff
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 1 participants
- Where
- 6 sitesUnited States
- Study dates
- 15 Nov 2022to 10 Oct 2023
- Phase
- Interventional
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
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 15 years and older
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- Diagnosis of patellofemoral pain syndrome (PFPS) or non-specific anterior knee pain (NSAKP) and plan to attend Gaylord Specialty Healthcare Physical Therapy
Who cannot join
- Member of a defined vulnerable population, women who are or suspected to be pregnant, prisoners, children under 15, or other protected populations
- Body mass of the leg preventing the cuff from fitting properly
- Radiographic evidence of osteoarthritis (≥ Kellgren-Lawrence Grade 2)
- History of intra-articular injection into either knee within 3 -months
- Uncontrolled or untreated inflammatory disorder
- Acute inflammatory disorder
Show all 20Show fewer
- Uncontrolled Diabetes and/or peripheral neuropathy, impaired circulation
- Uncontrolled cardiac conditions including uncontrolled hypertension
- Areas of thrombophlebitis, thrombosis
- Distal wounds or pain below the knee >4/10
- History of or current rhabdomyolysis
- Prolonged immobilization (>3 months)
- Sickle cell anemia
- Lymphadenectomy
- Varicose veins, or a history of personal or immediate family history (parental or sibling) of deep vein thrombosis
- Current infection at or below the level of cuff placement
- Malignancies in or below the area to be treated
- Other conditions/medications that would interfere with subject safety or data collection in the opinion of the PI
- Subjects with an increased risk of non-response as determined by the therapist
- Once entered in the study, a diagnosis change that affects participation
Trial locations and contacts
6 sites in 1 country.
6 sites in 1 country
United States6 sites
Gaylord Specialty Healthcare Outpatient Physical Therapy; Cheshire
Cheshire, Connecticut, 06410
Gaylord Specialty Healthcare Outpatient Physical Therapy; Cromwell
Cromwell, Connecticut, 06416
University of Connecticut Health Center
Farmington, Connecticut, 06030
Gaylord Specialty Healthcare Outpatient Physical Therapy; Madison
Madison, Connecticut, 06443
Gaylord Hospital
Wallingford, Connecticut, 06492
Gaylord Specialty Healthcare Outpatient Physical Therapy; Wallingford
Wallingford, Connecticut, 06492
About this study
The purpose of this study is to determine if Blood Flow Restriction therapy improves patient related outcomes in those diagnosed with Patellofemoral Pain Syndrome compared to those in the sham comparator control group.
Read the detailed description
Patellofemoral Pain Syndrome (PFPS), also known as Non-Specific Anterior Knee Pain (AKP), is a non-specific musculoskeletal condition characterized by loss of function and pain localized to the patella. PFPS affects up to 22% of the general population yearly, with females affected more so than males. Adolescents (28%, mixed gender) and elite athletes (up to 35% in knee dominant sports such as cycling) are also commonly affected, making this a relatively widespread condition. Additionally, PFPS has a generally unfavorable prognosis, with up to 40% of individuals failing conservative treatment after 1 year, and 57% reporting continued symptoms for 5 to 8-years following. Higher levels of baseline disability and longer duration of symptoms lead to an even poorer prognosis, making early recognition and novel treatments key. To complicate things further, the presence of negative psychosocial factors is commonly found in this population and may be a greater predictor of outcomes than physical ones.
Previously, biomechanical factors, such as maltracking of the patella and chondromalacia, have been called into question as potential causes of PFPS symptoms. However, both are now thought to be potential consequences of having PFPS. That being said, PFPS is generally accepted as a non-specific condition as there may be a number of different structures implicated as potential nociceptive drivers, and determining the exact tissue does not seem to be important to overall management strategies. This finding, in connection with the high prevalence of negative psychosocial factors, points less to a physiologically driven condition, and more towards a pain driven condition. While this theoretically makes diagnosing and treatment selection more ubiquitous, there does not seem to be a clear treatment strategy that works best for all patients. Despite a clear biomechanical cause, adjusting exercise selection or technique to include different loads and forces on the patella is still warranted based on patient presentation. For example, during open chain knee extension, the lowest loads are placed on the patella between 90- and 45-degree flexion, and open chain between 0 and 60 degrees. People with PFPS often benefit from adjusting the exercise selection, technique and load.
Recent research compared multiple different exercise strategies (combined core and hip work, knee work only, and open vs closed-chain), without any one program showing significant advantage over the others. A combination of these approaches may be best. One theme within PFPS exercise research that appears consistent is the high level of sensitivity and poor response to treatment where higher levels of pain are present. This is in contrast to tendon related pain, such as patellar tendinopathy, where working into moderate levels of pain seems to be helpful for outcomes.
The main mechanism driving improvements following exercise therapy for PFPS is not hypertrophy, but rather thought to be exercise induced hypoalgesia. This is a phenomenon where performing both acute bouts, as well as regular exercise (aerobic and resistance), reduces pain both in the short and long terms. Since exercise seems to reduce pain in both local and distant sites of the exercising area, it is thought to provide both local and systemic pain reducing effects. The magnitude and duration of the exercise seems to play an important role as well, with higher intensity and longer durations of exercising producing greater effects.
Since patients with PFPS are unable to achieve these desired parameters, alternative strategies need to be investigated. Two options may be blood flow restriction (BFR) therapy and low load training to failure, both of which may capture some of the hypoalgesic effects while minimizing AKP. BFR involves the application of an external device to reduce arterial blood flow to the exercising area, while largely occluding venous return from that same area. Exercise intensities generally range from 20-30% of the patients' 1 repetition maximum (1RM) weight, with relatively high repetitions (sometimes to failure); this is opposed to traditional resistance training at 70%+ of 1RM. BFR training has been demonstrated to amplify the effects of exercise induced hypoalgesia (in addition to a host of other physiological benefits) through unconfirmed mechanisms. Leading theories suggest that the lack of available oxygen to the exercising area may lead to: the activation of the endogenous opioid and cannabinoid systems; systemic changes to the cardiovascular system; or increased number of metabolites such as hydrogen ions and lactic acid, which may also be contributing factors.
Clinical research on the application of BFR in patients with PFPS has been both limited and mixed, with only two trials having been conducted in this area. One study from 2017 looked at high-load with BFR placebo, versus low-load BFR with leg press and knee extensions. Only the high-load group showed a modest medium-term effect on pain, lowering it for ~24 hours after BFR over the training period. The other paper from 2022 included both knee and hip strengthening exercises, comparing a low-load BFR group versus a high-load training group with no placebo; of note, the programs were not equated in terms of exercises completed. In this study, no significant difference was observed between groups. To date, there have been limited to no sham arms in studies where a BFR cuff was used. Given the potential for placebo effects, this was an important consideration in the design of the study.
Given the heterogeneity of these two studies, and the paucity of research in this area, the aim of the current study is to compare a low load training to failure (with BFR placebo) to low load BFR training to failure on the effect of pain related outcomes, function, strength and other measures. We hypothesize that BFR training will improve objective and subjective outcomes in patients with patellofemoral pain syndrome (PFPS) more than standard therapy with a sham BFR cuff.
Research aim 1: Determine whether the use of BFR improves patient-perceived function through a series of subjective patient-reported outcome measurements (PROs) throughout long-term recovery compared to patients in the sham control group. While we anticipate both groups may show improvement over time, we hypothesize that patients using BFR and the prescribed physical therapy protocol will demonstrate significantly improved PRO scores compared to the sham control group. These PROs include the Lower Extremity Functional Scale (LEFS), Knee Injury and Osteoarthritis Outcome Score for Patellofemoral Pain (KOOS-PF), the Single Assessment Numerical Evaluation (SANE), the Fear Avoidance Beliefs Questionnaire (FABQ), and Numerical Rating Scale (NRS) Pain Scale 1-10. Participants will be asked to complete PRO at the start of physical therapy (i.e. baseline), 4-weeks, 9-weeks or patient discharge if it is before the scheduled 9-week assessment, 6-month, and 12-month timepoints.
Research aim 2: Determine whether the use of BFR improves objective outcome measurements throughout prescribed physical therapy sessions compared to patients in the control group. While we anticipate both groups may show improvement over time, we hypothesize that patients using BFR and the prescribed physical therapy protocol will demonstrate significantly improved quadriceps isometric strength over the sham control group. Outcomes will be measured at the start of the physical therapy (i.e. baseline), 4-weeks, and 9-weeks or patient discharge if it is before the scheduled 9-week assessment.
- Being tested
- Blood Flow Restriction Cuff, Sham and standard of Care Therapy
- Keywords
- Blood Flow Restriction, Patellofemoral Pain Syndrome, Physical Therapy, Non-Specific Anterior Knee Pain
- Medical subject headings
- Patellofemoral Pain Syndrome
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Blood Flow Restriction CuffDevice
Blood Flow Restriction (BFR) involves the application of an external device to reduce arterial blood flow to the exercising area, while largely occluding venous return from that same area.
Sham and standard of Care TherapyProcedure or surgery
SoC PT + non-inflated BFR cuff
| Study group | Role | What they receive |
|---|---|---|
| Blood flow restriction and standard of care therapy | Experimental | The experimental BFR therapy will be incorporated into the standard therapy sessions and will not elongate the treatment session, quantity of sessions or incur any additional cost. As the participant progresses over time in therapy sessions, the discretion of the PT will determine when they have graduated beyond receiving any benefit from BFRT as demonstrated by quad strength. Receives: Device: Blood Flow Restriction Cuff |
| Sham and standard of care therapy | Placebo comparator | The sham comparator control group will also follow the Exercise Protocol in their physical therapy sessions with a non inflated blood flow restriction cuff attached in the same position as the experimental group. Similar to the intervention group, as participant's progress in therapy, the Physical Therapist will use their clinical decision making to advance the person through resistance and repetition increases. Receives: Procedure: Sham and standard of Care Therapy |
What is being measured
The primary outcome is the main question the study is designed to answer.
Numeric Pain Rating Scale: Enrollment
The Numeric Pain Rating Scale is one question pain intensity scale that assesses the current, best, and worst pain level in the last 24 hours
Measured: This assessment will be collected upon enrollment in the study.
Numeric Pain Rating Scale: 1 Week
The Numeric Pain Rating Scale is one question pain intensity scale that assesses the current, best, and worst pain level in the last 24 hours
Measured: This assessment will be collected 1-week into treatment
Numeric Pain Rating Scale: 4 Weeks
The Numeric Pain Rating Scale is one question pain intensity scale that assesses the current, best, and worst pain level in the last 24 hours
Measured: This assessment will be collected 4-weeks into treatment.
Numeric Pain Rating Scale: 9 Weeks/Discharge
The Numeric Pain Rating Scale is one question pain intensity scale that assesses the current, best, and worst pain level in the last 24 hours
Measured: This assessment will be collected 9-weeks into treatment or at discharge, whatever comes first.
Numeric Pain Rating Scale: 6 Months
The Numeric Pain Rating Scale is one question pain intensity scale that assesses the current, best, and worst pain level in the last 24 hours
Measured: This assessment will be collected 6 months post start date.
Numeric Pain Rating Scale: 12 Months
The Numeric Pain Rating Scale is one question pain intensity scale that assesses the current, best, and worst pain level in the last 24 hours
Measured: This assessment will be collected 12 months post start date.
Lower Extremity Functional Scale: Enrollment
The LEFS is a 20 question survey that is a valid PROM used for the measurement of lower extremity function based on the patients' initial function, ongoing progress, and long-term outcome
Measured: This assessment will be collected upon enrollment in the study.
Lower Extremity Functional Scale: 1 Week
The LEFS is a 20 question survey that is a valid PROM used for the measurement of lower extremity function based on the patients' initial function, ongoing progress, and long-term outcome
Measured: This assessment will be collected 1-week into treatment.
Lower Extremity Functional Scale: 4 Weeks
The LEFS is a 20 question survey that is a valid PROM used for the measurement of lower extremity function based on the patients' initial function, ongoing progress, and long-term outcome
Measured: This assessment will be collected 4-weeks into treatment.
Lower Extremity Functional Scale: 9 Weeks/Discharge
The LEFS is a 20 question survey that is a valid PROM used for the measurement of lower extremity function based on the patients' initial function, ongoing progress, and long-term outcome
Measured: This assessment will be collected 9-weeks into treatment or at discharge, whatever comes first.
Lower Extremity Functional Scale: 6 Months
The LEFS is a 20 question survey that is a valid PROM used for the measurement of lower extremity function based on the patients' initial function, ongoing progress, and long-term outcome
Measured: This assessment will be collected 6 months post start date.
Lower Extremity Functional Scale: 12 Months
The LEFS is a 20 question survey that is a valid PROM used for the measurement of lower extremity function based on the patients' initial function, ongoing progress, and long-term outcome
Measured: This assessment will be collected 12 months post start date.
Knee Injury and Osteoarthritis Outcome Score for Patellofemoral Pain: Enrollment
The KOOS-PF is an 11 question survey that is used to assess five outcomes; they include knee related Quality of Life, activities of daily living, sport and recreation function, activities, pain and symptoms
Measured: This assessment will be collected upon enrollment in the study.
Knee Injury and Osteoarthritis Outcome Score for Patellofemoral Pain: 1 Week
The KOOS-PF is an 11 question survey that is used to assess five outcomes; they include knee related Quality of Life, activities of daily living, sport and recreation function, activities, pain and symptoms
Measured: This assessment will be collected1-week into treatment.
Knee Injury and Osteoarthritis Outcome Score for Patellofemoral Pain: 4 Weeks
The KOOS-PF is an 11 question survey that is used to assess five outcomes; they include knee related Quality of Life, activities of daily living, sport and recreation function, activities, pain and symptoms
Measured: This assessment will be collected 4-weeks into treatment.
Knee Injury and Osteoarthritis Outcome Score for Patellofemoral Pain: 9 Weeks/Discharge
The KOOS-PF is an 11 question survey that is used to assess five outcomes; they include knee related Quality of Life, activities of daily living, sport and recreation function, activities, pain and symptoms
Measured: This assessment will be collected 9-weeks into treatment or at discharge, whatever comes first.
Knee Injury and Osteoarthritis Outcome Score for Patellofemoral Pain: 6 Months
The KOOS-PF is an 11 question survey that is used to assess five outcomes; they include knee related Quality of Life, activities of daily living, sport and recreation function, activities, pain and symptoms
Measured: This assessment will be collected 6 months post start date.
Knee Injury and Osteoarthritis Outcome Score for Patellofemoral Pain: 12 Months
The KOOS-PF is an 11 question survey that is used to assess five outcomes; they include knee related Quality of Life, activities of daily living, sport and recreation function, activities, pain and symptoms
Measured: This assessment will be collected 12 months post start date.
Single Assessment Numerical Evaluation: Enrollment
The SANE is a two item questionnaire used globally to assess function
Measured: This assessment will be collected upon enrollment in the study.
Single Assessment Numerical Evaluation: 1 Week
The SANE is a two item questionnaire used globally to assess function
Measured: This assessment will be collected 1-week into treatment.
Single Assessment Numerical Evaluation: 4 Weeks
The SANE is a two item questionnaire used globally to assess function
Measured: This assessment will be collected 4-weeks into treatment.
Single Assessment Numerical Evaluation: 9 Weeks/Discharge
The SANE is a two item questionnaire used globally to assess function
Measured: This assessment will be collected 9-weeks into treatment or at discharge, whatever comes first.
Single Assessment Numerical Evaluation: 6 Months
The SANE is a two item questionnaire used globally to assess function
Measured: This assessment will be collected 6 months post start date.
Single Assessment Numerical Evaluation: 12 Months
The SANE is a two item questionnaire used globally to assess function
Measured: This assessment will be collected 12 months post start date.
Tenger Activity Scale: Enrollment
The Tenger Activity Scale aims to provide a standardized method in determining the level of activity prior to injury and level of activity post injury that can be documented on a numerical scale.
Measured: This assessment will be collected upon enrollment.
Tenger Activity Scale: 6 Months
The Tenger Activity Scale aims to provide a standardized method in determining the level of activity prior to injury and level of activity post injury that can be documented on a numerical scale.
Measured: This assessment will be collected 6 months post start date.
Tenger Activity Scale: 12 Months
The Tenger Activity Scale aims to provide a standardized method in determining the level of activity prior to injury and level of activity post injury that can be documented on a numerical scale.
Measured: This assessment will be collected 12 months post start date.
Fear Avoidance Beliefs Questionnaire: Enrollment
The Fear Avoidance Belief Questionnaire is a 16 question likert scale questionnaire aimed at assessing how everyday activities assess the patient's current level of pain
Measured: This assessment will be collected upon enrollment in the study.
Fear Avoidance Beliefs Questionnaire: 1 Week
The Fear Avoidance Belief Questionnaire is a 16 question likert scale questionnaire aimed at assessing how everyday activities assess the patient's current level of pain
Measured: This assessment will be collected 1-week into treatment.
Fear Avoidance Beliefs Questionnaire: 4 Weeks
The Fear Avoidance Belief Questionnaire is a 16 question likert scale questionnaire aimed at assessing how everyday activities assess the patient's current level of pain
Measured: This assessment will be collected 4-weeks into treatment.
Fear Avoidance Beliefs Questionnaire: 9 Weeks/Discharge
The Fear Avoidance Belief Questionnaire is a 16 question likert scale questionnaire aimed at assessing how everyday activities assess the patient's current level of pain
Measured: This assessment will be collected 9-weeks into treatment or at discharge, whatever comes first.
Fear Avoidance Beliefs Questionnaire: 6 Months
The Fear Avoidance Belief Questionnaire is a 16 question likert scale questionnaire aimed at assessing how everyday activities assess the patient's current level of pain
Measured: This assessment will be collected 6 months post start date.
Fear Avoidance Beliefs Questionnaire: 12 Months
The Fear Avoidance Belief Questionnaire is a 16 question likert scale questionnaire aimed at assessing how everyday activities assess the patient's current level of pain
Measured: This assessment will be collected 12 months post start date.
Secondary outcomes (4)
Quadricep Isometric Strength: Enrollment
Quadricep Isometric Strength is the amount of strength shown in a patient's quadricep muscle via isometric dynomometry
Measured: This assessment will be collected upon enrollment in the study.
Quadricep Isometric Strength: 1 Week
Quadricep Isometric Strength is the amount of strength shown in a patient's quadricep muscle via isometric dynomometry
Measured: This assessment will be collected 1-week into treatment.
Quadricep Isometric Strength: 4 Weeks
Quadricep Isometric Strength is the amount of strength shown in a patient's quadricep muscle via isometric dynomometry
Measured: This assessment will be collected 4-weeks into treatment.
Quadricep Isometric Strength: 9 Weeks/Discharge
Quadricep Isometric Strength is the amount of strength shown in a patient's quadricep muscle via isometric dynomometry
Measured: This assessment will be collected 9-weeks into treatment or at discharge, whatever comes first.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Nov 2022
- Study start15 Nov 2022
- Primary completion10 Oct 2023
- Study completion10 Oct 2023
Why it stopped: Study terminated due to lack of recruitment.
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (18)Papers the sponsor has linked to this study.
- Other trials for Patellofemoral Pain SyndromeStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
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
- None (open label)
- Enrolment
- 1 participants (actual)
Sponsor and investigators
- Lead sponsor
- Gaylord Hospital, Inc
- Sponsor type
- University, hospital or other
- Collaborators
- UConn Health
- Responsible party
- Sponsor
- Investigators
- Eric Sokolowski, Principal investigator, Physical TherapistDanielle Letendre, Principal investigator, Physical Therapist
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05617911
- Sponsor's protocol ID
- 202209SOK
- Status last verified
- Nov 2025
- First submitted
- 1 Nov 2022
- Last updated
- 10 Dec 2025
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- Yes: Deidentified data will become available to researchers that are interesting after analysis has been completed. Data will be available for 3 years after the date of completion.
Publications
Smith BE, Selfe J, Thacker D, Hendrick P, Bateman M, Moffatt F, Rathleff MS, Smith TO, Logan P. Incidence and prevalence of patellofemoral pain: A systematic review and meta-analysis. PLoS One. 2018 Jan 11;13(1):e0190892. doi: 10.1371/journal.pone.0190892. eCollection 2018.
PubMed 29324820Collins NJ, Bierma-Zeinstra SM, Crossley KM, van Linschoten RL, Vicenzino B, van Middelkoop M. Prognostic factors for patellofemoral pain: a multicentre observational analysis. Br J Sports Med. 2013 Mar;47(4):227-33. doi: 10.1136/bjsports-2012-091696. Epub 2012 Dec 13.
PubMed 23242955Lankhorst NE, van Middelkoop M, Crossley KM, Bierma-Zeinstra SM, Oei EH, Vicenzino B, Collins NJ. Factors that predict a poor outcome 5-8 years after the diagnosis of patellofemoral pain: a multicentre observational analysis. Br J Sports Med. 2016 Jul;50(14):881-6. doi: 10.1136/bjsports-2015-094664. Epub 2015 Oct 13.
PubMed 26463119Maclachlan LR, Matthews M, Hodges PW, Collins NJ, Vicenzino B. The psychological features of patellofemoral pain: a cross-sectional study. Scand J Pain. 2018 Apr 25;18(2):261-271. doi: 10.1515/sjpain-2018-0025.
PubMed 29794307Post WR, Dye SF. Patellofemoral Pain: An Enigma Explained by Homeostasis and Common Sense. Am J Orthop (Belle Mead NJ). 2017 Mar/Apr;46(2):92-100.
PubMed 28437494Saltychev M, Dutton RA, Laimi K, Beaupre GS, Virolainen P, Fredericson M. Effectiveness of conservative treatment for patellofemoral pain syndrome: A systematic review and meta-analysis. J Rehabil Med. 2018 May 8;50(5):393-401. doi: 10.2340/16501977-2295.
PubMed 29392329Powers CM, Ho KY, Chen YJ, Souza RB, Farrokhi S. Patellofemoral joint stress during weight-bearing and non-weight-bearing quadriceps exercises. J Orthop Sports Phys Ther. 2014 May;44(5):320-7. doi: 10.2519/jospt.2014.4936. Epub 2014 Mar 27.
PubMed 24673446Collins NJ, Barton CJ, van Middelkoop M, Callaghan MJ, Rathleff MS, Vicenzino BT, Davis IS, Powers CM, Macri EM, Hart HF, de Oliveira Silva D, Crossley KM. 2018 Consensus statement on exercise therapy and physical interventions (orthoses, taping and manual therapy) to treat patellofemoral pain: recommendations from the 5th International Patellofemoral Pain Research Retreat, Gold Coast, Australia, 2017. Br J Sports Med. 2018 Sep;52(18):1170-1178. doi: 10.1136/bjsports-2018-099397. Epub 2018 Jun 20.
PubMed 29925502Kountouris A, Cook J. Rehabilitation of Achilles and patellar tendinopathies. Best Pract Res Clin Rheumatol. 2007 Apr;21(2):295-316. doi: 10.1016/j.berh.2006.12.003.
PubMed 17512484Song JS, Spitz RW, Yamada Y, Bell ZW, Wong V, Abe T, Loenneke JP. Exercise-induced hypoalgesia and pain reduction following blood flow restriction: A brief review. Phys Ther Sport. 2021 Jul;50:89-96. doi: 10.1016/j.ptsp.2021.04.005. Epub 2021 Apr 23.
PubMed 33940556Misra G, Paris TA, Archer DB, Coombes SA. Dose-response effect of isometric force production on the perception of pain. PLoS One. 2014 Feb 4;9(2):e88105. doi: 10.1371/journal.pone.0088105. eCollection 2014.
PubMed 24505397Hughes L, Patterson SD. The effect of blood flow restriction exercise on exercise-induced hypoalgesia and endogenous opioid and endocannabinoid mechanisms of pain modulation. J Appl Physiol (1985). 2020 Apr 1;128(4):914-924. doi: 10.1152/japplphysiol.00768.2019. Epub 2020 Feb 27.
PubMed 32105522Giles L, Webster KE, McClelland J, Cook JL. Quadriceps strengthening with and without blood flow restriction in the treatment of patellofemoral pain: a double-blind randomised trial. Br J Sports Med. 2017 Dec;51(23):1688-1694. doi: 10.1136/bjsports-2016-096329. Epub 2017 May 12.
PubMed 28500081Constantinou A, Mamais I, Papathanasiou G, Lamnisos D, Stasinopoulos D. Comparing hip and knee focused exercises versus hip and knee focused exercises with the use of blood flow restriction training in adults with patellofemoral pain. Eur J Phys Rehabil Med. 2022 Apr;58(2):225-235. doi: 10.23736/S1973-9087.22.06691-6. Epub 2022 Jan 5.
PubMed 34985237Dolak KL, Silkman C, Medina McKeon J, Hosey RG, Lattermann C, Uhl TL. Hip strengthening prior to functional exercises reduces pain sooner than quadriceps strengthening in females with patellofemoral pain syndrome: a randomized clinical trial. J Orthop Sports Phys Ther. 2011 Aug;41(8):560-70. doi: 10.2519/jospt.2011.3499. Epub 2011 Jun 7.
PubMed 21654093
Study at a glance
From the registry record, last updated by the sponsor on 10 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Clinical Comparison of Patellofemoral Pain Syndrome Outcomes After Blood Flow Restriction Therapy
- ClinicalTrials.gov ID
- NCT05617911
- Acronym / sponsor ID
- 202209SOK
- Keywords
- Blood Flow Restriction, Patellofemoral Pain Syndrome, Physical Therapy, Non-Specific Anterior Knee Pain
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: Study terminated due to lack of recruitment.
- Enrolment
- 1 participants (actual)
- Lead sponsor
- Gaylord Hospital, IncUniversity, hospital or other
- Collaborators
- UConn Health
- Study start
- 15 Nov 2022 (actual)
- Primary completion
- 10 Oct 2023 (actual)
- Study completion
- 10 Oct 2023 (actual)
- First posted
- 16 Nov 2022 (actual)
- Results
- Posted 10 Dec 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to determine if Blood Flow Restriction therapy improves patient related outcomes in those diagnosed with Patellofemoral Pain Syndrome compared to those in the sham comparator control group.
Detailed description
Patellofemoral Pain Syndrome (PFPS), also known as Non-Specific Anterior Knee Pain (AKP), is a non-specific musculoskeletal condition characterized by loss of function and pain localized to the patella. PFPS affects up to 22% of the general population yearly, with females affected more so than males. Adolescents (28%, mixed gender) and elite athletes (up to 35% in knee dominant sports such as cycling) are also commonly affected, making this a relatively widespread condition. Additionally, PFPS has a generally unfavorable prognosis, with up to 40% of individuals failing conservative treatment after 1 year, and 57% reporting continued symptoms for 5 to 8-years following. Higher levels of baseline disability and longer duration of symptoms lead to an even poorer prognosis, making early recognition and novel treatments key. To complicate things further, the presence of negative psychosocial factors is commonly found in this population and may be a greater predictor of outcomes than physical ones.
Previously, biomechanical factors, such as maltracking of the patella and chondromalacia, have been called into question as potential causes of PFPS symptoms. However, both are now thought to be potential consequences of having PFPS. That being said, PFPS is generally accepted as a non-specific condition as there may be a number of different structures implicated as potential nociceptive drivers, and determining the exact tissue does not seem to be important to overall management strategies. This finding, in connection with the high prevalence of negative psychosocial factors, points less to a physiologically driven condition, and more towards a pain driven condition. While this theoretically makes diagnosing and treatment selection more ubiquitous, there does not seem to be a clear treatment strategy that works best for all patients. Despite a clear biomechanical cause, adjusting exercise selection or technique to include different loads and forces on the patella is still warranted based on patient presentation. For example, during open chain knee extension, the lowest loads are placed on the patella between 90- and 45-degree flexion, and open chain between 0 and 60 degrees. People with PFPS often benefit from adjusting the exercise selection, technique and load.
Recent research compared multiple different exercise strategies (combined core and hip work, knee work only, and open vs closed-chain), without any one program showing significant advantage over the others. A combination of these approaches may be best. One theme within PFPS exercise research that appears consistent is the high level of sensitivity and poor response to treatment where higher levels of pain are present. This is in contrast to tendon related pain, such as patellar tendinopathy, where working into moderate levels of pain seems to be helpful for outcomes.
The main mechanism driving improvements following exercise therapy for PFPS is not hypertrophy, but rather thought to be exercise induced hypoalgesia. This is a phenomenon where performing both acute bouts, as well as regular exercise (aerobic and resistance), reduces pain both in the short and long terms. Since exercise seems to reduce pain in both local and distant sites of the exercising area, it is thought to provide both local and systemic pain reducing effects. The magnitude and duration of the exercise seems to play an important role as well, with higher intensity and longer durations of exercising producing greater effects.
Since patients with PFPS are unable to achieve these desired parameters, alternative strategies need to be investigated. Two options may be blood flow restriction (BFR) therapy and low load training to failure, both of which may capture some of the hypoalgesic effects while minimizing AKP. BFR involves the application of an external device to reduce arterial blood flow to the exercising area, while largely occluding venous return from that same area. Exercise intensities generally range from 20-30% of the patients' 1 repetition maximum (1RM) weight, with relatively high repetitions (sometimes to failure); this is opposed to traditional resistance training at 70%+ of 1RM. BFR training has been demonstrated to amplify the effects of exercise induced hypoalgesia (in addition to a host of other physiological benefits) through unconfirmed mechanisms. Leading theories suggest that the lack of available oxygen to the exercising area may lead to: the activation of the endogenous opioid and cannabinoid systems; systemic changes to the cardiovascular system; or increased number of metabolites such as hydrogen ions and lactic acid, which may also be contributing factors.
Clinical research on the application of BFR in patients with PFPS has been both limited and mixed, with only two trials having been conducted in this area. One study from 2017 looked at high-load with BFR placebo, versus low-load BFR with leg press and knee extensions. Only the high-load group showed a modest medium-term effect on pain, lowering it for ~24 hours after BFR over the training period. The other paper from 2022 included both knee and hip strengthening exercises, comparing a low-load BFR group versus a high-load training group with no placebo; of note, the programs were not equated in terms of exercises completed. In this study, no significant difference was observed between groups. To date, there have been limited to no sham arms in studies where a BFR cuff was used. Given the potential for placebo effects, this was an important consideration in the design of the study.
Given the heterogeneity of these two studies, and the paucity of research in this area, the aim of the current study is to compare a low load training to failure (with BFR placebo) to low load BFR training to failure on the effect of pain related outcomes, function, strength and other measures. We hypothesize that BFR training will improve objective and subjective outcomes in patients with patellofemoral pain syndrome (PFPS) more than standard therapy with a sham BFR cuff.
Research aim 1: Determine whether the use of BFR improves patient-perceived function through a series of subjective patient-reported outcome measurements (PROs) throughout long-term recovery compared to patients in the sham control group. While we anticipate both groups may show improvement over time, we hypothesize that patients using BFR and the prescribed physical therapy protocol will demonstrate significantly improved PRO scores compared to the sham control group. These PROs include the Lower Extremity Functional Scale (LEFS), Knee Injury and Osteoarthritis Outcome Score for Patellofemoral Pain (KOOS-PF), the Single Assessment Numerical Evaluation (SANE), the Fear Avoidance Beliefs Questionnaire (FABQ), and Numerical Rating Scale (NRS) Pain Scale 1-10. Participants will be asked to complete PRO at the start of physical therapy (i.e. baseline), 4-weeks, 9-weeks or patient discharge if it is before the scheduled 9-week assessment, 6-month, and 12-month timepoints.
Research aim 2: Determine whether the use of BFR improves objective outcome measurements throughout prescribed physical therapy sessions compared to patients in the control group. While we anticipate both groups may show improvement over time, we hypothesize that patients using BFR and the prescribed physical therapy protocol will demonstrate significantly improved quadriceps isometric strength over the sham control group. Outcomes will be measured at the start of the physical therapy (i.e. baseline), 4-weeks, and 9-weeks or patient discharge if it is before the scheduled 9-week assessment.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Blood flow restriction and standard of care therapy | Experimental | Device: Blood Flow Restriction CuffThe experimental BFR therapy will be incorporated into the standard therapy sessions and will not elongate the treatment session, quantity of sessions or incur any additional cost. As the participant progresses over time in therapy sessions, the discretion of the PT will determine when they have graduated beyond receiving any benefit from BFRT as demonstrated by quad strength. |
| Sham and standard of care therapy | Placebo comparator | Procedure: Sham and standard of Care TherapyThe sham comparator control group will also follow the Exercise Protocol in their physical therapy sessions with a non inflated blood flow restriction cuff attached in the same position as the experimental group. Similar to the intervention group, as participant's progress in therapy, the Physical Therapist will use their clinical decision making to advance the person through resistance and repetition increases. |
Who may qualify
- Ages
- 15 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (1 listed)
- Diagnosis of patellofemoral pain syndrome (PFPS) or non-specific anterior knee pain (NSAKP) and plan to attend Gaylord Specialty Healthcare Physical Therapy
Key exclusion criteria (20 listed)
- Member of a defined vulnerable population, women who are or suspected to be pregnant, prisoners, children under 15, or other protected populations
- Body mass of the leg preventing the cuff from fitting properly
- Radiographic evidence of osteoarthritis (≥ Kellgren-Lawrence Grade 2)
- History of intra-articular injection into either knee within 3 -months
- Uncontrolled or untreated inflammatory disorder
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Blood Flow Restriction CuffBlood Flow Restriction (BFR) involves the application of an external device to reduce arterial blood flow to the exercising area, while largely occluding venous return from that same area. | Device | Blood flow restriction and standard of care therapy |
| Sham and standard of Care TherapySoC PT + non-inflated BFR cuff | Procedure or surgery | Sham and standard of care therapy |
Primary outcome
Numeric Pain Rating Scale: Enrollment
Time frame: This assessment will be collected upon enrollment in the study.
The Numeric Pain Rating Scale is one question pain intensity scale that assesses the current, best, and worst pain level in the last 24 hours
Numeric Pain Rating Scale: 1 Week
Time frame: This assessment will be collected 1-week into treatment
The Numeric Pain Rating Scale is one question pain intensity scale that assesses the current, best, and worst pain level in the last 24 hours
Numeric Pain Rating Scale: 4 Weeks
Time frame: This assessment will be collected 4-weeks into treatment.
The Numeric Pain Rating Scale is one question pain intensity scale that assesses the current, best, and worst pain level in the last 24 hours
Numeric Pain Rating Scale: 9 Weeks/Discharge
Time frame: This assessment will be collected 9-weeks into treatment or at discharge, whatever comes first.
The Numeric Pain Rating Scale is one question pain intensity scale that assesses the current, best, and worst pain level in the last 24 hours
Numeric Pain Rating Scale: 6 Months
Time frame: This assessment will be collected 6 months post start date.
The Numeric Pain Rating Scale is one question pain intensity scale that assesses the current, best, and worst pain level in the last 24 hours
Numeric Pain Rating Scale: 12 Months
Time frame: This assessment will be collected 12 months post start date.
The Numeric Pain Rating Scale is one question pain intensity scale that assesses the current, best, and worst pain level in the last 24 hours
Lower Extremity Functional Scale: Enrollment
Time frame: This assessment will be collected upon enrollment in the study.
The LEFS is a 20 question survey that is a valid PROM used for the measurement of lower extremity function based on the patients' initial function, ongoing progress, and long-term outcome
Lower Extremity Functional Scale: 1 Week
Time frame: This assessment will be collected 1-week into treatment.
The LEFS is a 20 question survey that is a valid PROM used for the measurement of lower extremity function based on the patients' initial function, ongoing progress, and long-term outcome
Lower Extremity Functional Scale: 4 Weeks
Time frame: This assessment will be collected 4-weeks into treatment.
The LEFS is a 20 question survey that is a valid PROM used for the measurement of lower extremity function based on the patients' initial function, ongoing progress, and long-term outcome
Lower Extremity Functional Scale: 9 Weeks/Discharge
Time frame: This assessment will be collected 9-weeks into treatment or at discharge, whatever comes first.
The LEFS is a 20 question survey that is a valid PROM used for the measurement of lower extremity function based on the patients' initial function, ongoing progress, and long-term outcome
Lower Extremity Functional Scale: 6 Months
Time frame: This assessment will be collected 6 months post start date.
The LEFS is a 20 question survey that is a valid PROM used for the measurement of lower extremity function based on the patients' initial function, ongoing progress, and long-term outcome
Lower Extremity Functional Scale: 12 Months
Time frame: This assessment will be collected 12 months post start date.
The LEFS is a 20 question survey that is a valid PROM used for the measurement of lower extremity function based on the patients' initial function, ongoing progress, and long-term outcome
Knee Injury and Osteoarthritis Outcome Score for Patellofemoral Pain: Enrollment
Time frame: This assessment will be collected upon enrollment in the study.
The KOOS-PF is an 11 question survey that is used to assess five outcomes; they include knee related Quality of Life, activities of daily living, sport and recreation function, activities, pain and symptoms
Knee Injury and Osteoarthritis Outcome Score for Patellofemoral Pain: 1 Week
Time frame: This assessment will be collected1-week into treatment.
The KOOS-PF is an 11 question survey that is used to assess five outcomes; they include knee related Quality of Life, activities of daily living, sport and recreation function, activities, pain and symptoms
Knee Injury and Osteoarthritis Outcome Score for Patellofemoral Pain: 4 Weeks
Time frame: This assessment will be collected 4-weeks into treatment.
The KOOS-PF is an 11 question survey that is used to assess five outcomes; they include knee related Quality of Life, activities of daily living, sport and recreation function, activities, pain and symptoms
Knee Injury and Osteoarthritis Outcome Score for Patellofemoral Pain: 9 Weeks/Discharge
Time frame: This assessment will be collected 9-weeks into treatment or at discharge, whatever comes first.
The KOOS-PF is an 11 question survey that is used to assess five outcomes; they include knee related Quality of Life, activities of daily living, sport and recreation function, activities, pain and symptoms
Knee Injury and Osteoarthritis Outcome Score for Patellofemoral Pain: 6 Months
Time frame: This assessment will be collected 6 months post start date.
The KOOS-PF is an 11 question survey that is used to assess five outcomes; they include knee related Quality of Life, activities of daily living, sport and recreation function, activities, pain and symptoms
Knee Injury and Osteoarthritis Outcome Score for Patellofemoral Pain: 12 Months
Time frame: This assessment will be collected 12 months post start date.
The KOOS-PF is an 11 question survey that is used to assess five outcomes; they include knee related Quality of Life, activities of daily living, sport and recreation function, activities, pain and symptoms
Single Assessment Numerical Evaluation: Enrollment
Time frame: This assessment will be collected upon enrollment in the study.
The SANE is a two item questionnaire used globally to assess function
Single Assessment Numerical Evaluation: 1 Week
Time frame: This assessment will be collected 1-week into treatment.
The SANE is a two item questionnaire used globally to assess function
Single Assessment Numerical Evaluation: 4 Weeks
Time frame: This assessment will be collected 4-weeks into treatment.
The SANE is a two item questionnaire used globally to assess function
Single Assessment Numerical Evaluation: 9 Weeks/Discharge
Time frame: This assessment will be collected 9-weeks into treatment or at discharge, whatever comes first.
The SANE is a two item questionnaire used globally to assess function
Single Assessment Numerical Evaluation: 6 Months
Time frame: This assessment will be collected 6 months post start date.
The SANE is a two item questionnaire used globally to assess function
Single Assessment Numerical Evaluation: 12 Months
Time frame: This assessment will be collected 12 months post start date.
The SANE is a two item questionnaire used globally to assess function
Tenger Activity Scale: Enrollment
Time frame: This assessment will be collected upon enrollment.
The Tenger Activity Scale aims to provide a standardized method in determining the level of activity prior to injury and level of activity post injury that can be documented on a numerical scale.
Tenger Activity Scale: 6 Months
Time frame: This assessment will be collected 6 months post start date.
The Tenger Activity Scale aims to provide a standardized method in determining the level of activity prior to injury and level of activity post injury that can be documented on a numerical scale.
Tenger Activity Scale: 12 Months
Time frame: This assessment will be collected 12 months post start date.
The Tenger Activity Scale aims to provide a standardized method in determining the level of activity prior to injury and level of activity post injury that can be documented on a numerical scale.
Fear Avoidance Beliefs Questionnaire: Enrollment
Time frame: This assessment will be collected upon enrollment in the study.
The Fear Avoidance Belief Questionnaire is a 16 question likert scale questionnaire aimed at assessing how everyday activities assess the patient's current level of pain
Fear Avoidance Beliefs Questionnaire: 1 Week
Time frame: This assessment will be collected 1-week into treatment.
The Fear Avoidance Belief Questionnaire is a 16 question likert scale questionnaire aimed at assessing how everyday activities assess the patient's current level of pain
Fear Avoidance Beliefs Questionnaire: 4 Weeks
Time frame: This assessment will be collected 4-weeks into treatment.
The Fear Avoidance Belief Questionnaire is a 16 question likert scale questionnaire aimed at assessing how everyday activities assess the patient's current level of pain
Fear Avoidance Beliefs Questionnaire: 9 Weeks/Discharge
Time frame: This assessment will be collected 9-weeks into treatment or at discharge, whatever comes first.
The Fear Avoidance Belief Questionnaire is a 16 question likert scale questionnaire aimed at assessing how everyday activities assess the patient's current level of pain
Fear Avoidance Beliefs Questionnaire: 6 Months
Time frame: This assessment will be collected 6 months post start date.
The Fear Avoidance Belief Questionnaire is a 16 question likert scale questionnaire aimed at assessing how everyday activities assess the patient's current level of pain
Fear Avoidance Beliefs Questionnaire: 12 Months
Time frame: This assessment will be collected 12 months post start date.
The Fear Avoidance Belief Questionnaire is a 16 question likert scale questionnaire aimed at assessing how everyday activities assess the patient's current level of pain
4 secondary outcomes
Quadricep Isometric Strength: Enrollment
Time frame: This assessment will be collected upon enrollment in the study.
Quadricep Isometric Strength: 1 Week
Time frame: This assessment will be collected 1-week into treatment.
Quadricep Isometric Strength: 4 Weeks
Time frame: This assessment will be collected 4-weeks into treatment.
Quadricep Isometric Strength: 9 Weeks/Discharge
Time frame: This assessment will be collected 9-weeks into treatment or at discharge, whatever comes first.
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 10 Dec 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Background: PubMed 29324820Smith BE, Selfe J, Thacker D, Hendrick P, Bateman M, Moffatt F, Rathleff MS, Smith TO, Logan P. Incidence and prevalence of patellofemoral pain: A systematic review and meta-analysis. PLoS One. 2018 Jan 11;13(1):e0190892. doi: 10.1371/journal.pone.0190892. eCollection 2018.
- Background: PubMed 23242955Collins NJ, Bierma-Zeinstra SM, Crossley KM, van Linschoten RL, Vicenzino B, van Middelkoop M. Prognostic factors for patellofemoral pain: a multicentre observational analysis. Br J Sports Med. 2013 Mar;47(4):227-33. doi: 10.1136/bjsports-2012-091696. Epub 2012 Dec 13.
- Background: PubMed 26463119Lankhorst NE, van Middelkoop M, Crossley KM, Bierma-Zeinstra SM, Oei EH, Vicenzino B, Collins NJ. Factors that predict a poor outcome 5-8 years after the diagnosis of patellofemoral pain: a multicentre observational analysis. Br J Sports Med. 2016 Jul;50(14):881-6. doi: 10.1136/bjsports-2015-094664. Epub 2015 Oct 13.
- Background: PubMed 29794307Maclachlan LR, Matthews M, Hodges PW, Collins NJ, Vicenzino B. The psychological features of patellofemoral pain: a cross-sectional study. Scand J Pain. 2018 Apr 25;18(2):261-271. doi: 10.1515/sjpain-2018-0025.
- Background: PubMed 28437494Post WR, Dye SF. Patellofemoral Pain: An Enigma Explained by Homeostasis and Common Sense. Am J Orthop (Belle Mead NJ). 2017 Mar/Apr;46(2):92-100.
- Background: PubMed 29392329Saltychev M, Dutton RA, Laimi K, Beaupre GS, Virolainen P, Fredericson M. Effectiveness of conservative treatment for patellofemoral pain syndrome: A systematic review and meta-analysis. J Rehabil Med. 2018 May 8;50(5):393-401. doi: 10.2340/16501977-2295.
- Background: PubMed 24673446Powers CM, Ho KY, Chen YJ, Souza RB, Farrokhi S. Patellofemoral joint stress during weight-bearing and non-weight-bearing quadriceps exercises. J Orthop Sports Phys Ther. 2014 May;44(5):320-7. doi: 10.2519/jospt.2014.4936. Epub 2014 Mar 27.
- Background: PubMed 29925502Collins NJ, Barton CJ, van Middelkoop M, Callaghan MJ, Rathleff MS, Vicenzino BT, Davis IS, Powers CM, Macri EM, Hart HF, de Oliveira Silva D, Crossley KM. 2018 Consensus statement on exercise therapy and physical interventions (orthoses, taping and manual therapy) to treat patellofemoral pain: recommendations from the 5th International Patellofemoral Pain Research Retreat, Gold Coast, Australia, 2017. Br J Sports Med. 2018 Sep;52(18):1170-1178. doi: 10.1136/bjsports-2018-099397. Epub 2018 Jun 20.
- Background: PubMed 17512484Kountouris A, Cook J. Rehabilitation of Achilles and patellar tendinopathies. Best Pract Res Clin Rheumatol. 2007 Apr;21(2):295-316. doi: 10.1016/j.berh.2006.12.003.
- Background: PubMed 33940556Song JS, Spitz RW, Yamada Y, Bell ZW, Wong V, Abe T, Loenneke JP. Exercise-induced hypoalgesia and pain reduction following blood flow restriction: A brief review. Phys Ther Sport. 2021 Jul;50:89-96. doi: 10.1016/j.ptsp.2021.04.005. Epub 2021 Apr 23.
- Background: PubMed 24505397Misra G, Paris TA, Archer DB, Coombes SA. Dose-response effect of isometric force production on the perception of pain. PLoS One. 2014 Feb 4;9(2):e88105. doi: 10.1371/journal.pone.0088105. eCollection 2014.
- Background: PubMed 32105522Hughes L, Patterson SD. The effect of blood flow restriction exercise on exercise-induced hypoalgesia and endogenous opioid and endocannabinoid mechanisms of pain modulation. J Appl Physiol (1985). 2020 Apr 1;128(4):914-924. doi: 10.1152/japplphysiol.00768.2019. Epub 2020 Feb 27.
- Individual participant dataSharing planned: Yes. Deidentified data will become available to researchers that are interesting after analysis has been completed. Data will be available for 3 years after the date of completion.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Eric Sokolowski principal investigator
Physical Therapist
Danielle Letendre principal investigator
Physical Therapist
6 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Blood Flow Restriction Cuff in people with Patellofemoral Pain Syndrome and Anterior Knee Pain Syndrome, run by Gaylord Hospital, Inc at 6 sites in United States.
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 1 inclusion and 20 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: stopped early, as of the sponsor's last update on 10 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 6 sites in United States. 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. Some participants in this study may receive a placebo. 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?
Yes. Results are posted in the registry (first posted 10 Dec 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
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?
Numeric Pain Rating Scale: Enrollment (time frame: This assessment will be collected upon enrollment in the study.). The study lists 33 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 NCT05617911, which also lists 18 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 10 Dec 2025.