Clinical Comparison of Patellofemoral Pain Syndrome Outcomes After Blood Flow Restriction Therapy
NCT ID: NCT05617911
Last Updated: 2025-12-10
Study Results
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View full resultsBasic Information
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TERMINATED
NA
1 participants
INTERVENTIONAL
2022-11-15
2023-10-10
Brief Summary
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Detailed Description
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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.
Conditions
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Study Design
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RANDOMIZED
PARALLEL
TREATMENT
NONE
Study Groups
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Sham and standard of care therapy
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.
Sham and standard of Care Therapy
SoC PT + non-inflated BFR cuff
Blood flow restriction and standard of care therapy
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.
Blood Flow Restriction Cuff
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.
Interventions
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Blood Flow Restriction Cuff
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 Therapy
SoC PT + non-inflated BFR cuff
Eligibility Criteria
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Inclusion Criteria
Exclusion Criteria
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
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
15 Years
ALL
No
Sponsors
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UConn Health
OTHER
Gaylord Hospital, Inc
OTHER
Responsible Party
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Principal Investigators
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Eric Sokolowski
Role: PRINCIPAL_INVESTIGATOR
Physical Therapist
Danielle Letendre
Role: PRINCIPAL_INVESTIGATOR
Physical Therapist
Locations
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Gaylord Specialty Healthcare Outpatient Physical Therapy; Cheshire
Cheshire, Connecticut, United States
Gaylord Specialty Healthcare Outpatient Physical Therapy; Cromwell
Cromwell, Connecticut, United States
University of Connecticut Health Center
Farmington, Connecticut, United States
Gaylord Specialty Healthcare Outpatient Physical Therapy; Madison
Madison, Connecticut, United States
Gaylord Hospital
Wallingford, Connecticut, United States
Gaylord Specialty Healthcare Outpatient Physical Therapy; Wallingford
Wallingford, Connecticut, United States
Countries
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References
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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.
Collins 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.
Lankhorst 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.
Maclachlan 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.
Post 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.
Saltychev 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.
Powers 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.
Collins 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.
Kountouris 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.
Song 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.
Misra 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.
Hughes 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.
Giles 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.
Constantinou 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.
Dolak 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.
Sisk D, Fredericson M. Update of Risk Factors, Diagnosis, and Management of Patellofemoral Pain. Curr Rev Musculoskelet Med. 2019 Dec;12(4):534-541. doi: 10.1007/s12178-019-09593-z.
Brightwell BD, Stone A, Li X, Hardy P, Thompson K, Noehren B, Jacobs C. Blood flow Restriction training After patellar INStability (BRAINS Trial). Trials. 2022 Jan 28;23(1):88. doi: 10.1186/s13063-022-06017-1.
Thiebaud RS, Yasuda T, Loenneke JP, Abe T. Effects of low-intensity concentric and eccentric exercise combined with blood flow restriction on indices of exercise-induced muscle damage. Interv Med Appl Sci. 2013 Jun;5(2):53-9. doi: 10.1556/IMAS.5.2013.2.1. Epub 2013 Jul 4.
Provided Documents
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Document Type: Study Protocol and Statistical Analysis Plan
Other Identifiers
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202209SOK
Identifier Type: -
Identifier Source: org_study_id
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