Efficacy and Safety of Blood Flow Restriction Training in Patients With Knee Osteoarthritis: A Systematic Review and Meta-Analysis

Effects of Blood Flow Restriction Training on Strength and Functionality in People With Knee Arthropathies: A Systematic Review and Dose-Response Meta-Analysis of Randomized Controlled Trials

Background: Previous meta-analyses show contrasting findings regarding the effects of blood flow restriction training (BFRT) in different knee conditions. Furthermore, no previous dose-response analysis has been conducted to determine the dose of BFRT required for maximal strength and functionality adaptations. Objective: To analyze the evidence on the effects of BFRT on strength and functionality in patients with knee osteoarthritis or rheumatoid arthritis through a systematic review with dose-response meta-analysis. Methods: Included studies met the following criteria: participants with knee osteoarthritis or rheumatoid arthritis; low-load resistance BFRT as intervention; control group with traditional moderate or high intensity resistance training (MIRT and HIRT); include muscle strength and functionality as primary and secondary outcome measures, respectively; and only randomized controlled trials. A random-effects and a dose-response model estimated strength and functionality using estimates of the total repetitions performed. Results: We included five studies with a sample of 205 participants. No statistically significant differences were found between BFRT and MIRT or HIRT for strength (SMD = -0.06; 95% CI = -0.78-0.67; and p > 0.05) and functionality (SMD = 0.07; 95% CI = -0.23-0.37; and p > 0.05). We found an inverted U-shaped association between the increase in total repetitions and strength gain and between the increase in total repetitions and functional improvement. Conclusions: People with knee osteoarthritis or rheumatoid arthritis can use low-load BFRT for strength and functionality as a similarly effective alternative to MIRT and HIRT. A total of 2000 repetitions per BFRT program are necessary to maximize strength gains in these patients, while functional improvement requires 1800 total repetitions.

Impact of low-load blood flow restriction training on knee osteoarthritis pain and muscle strength: a systematic review and meta-analysis of randomized controlled trials

Objectives

The effectiveness of low-load blood flow restriction training (LL-BFRT) in alleviating symptoms in patients with knee osteoarthritis (KOA) remains inconclusive. This systematic review and meta-analysis aim to comprehensively assess the effects of LL-BFRT compared to conventional resistance training on pain, muscle strength, and functional capacity in individuals with KOA.

Data sources

PubMed, Embase, Web of Science, EBSCO, Scopus, and Cochrane trails were searched.

Study selection

We included randomized controlled trials involving patients with KOA, in which the intervention group underwent LL-BFRT.

Data extraction

Literature quality and risk of bias were assessed using the Physiotherapy Evidence Database (PEDro) scale and the Cochrane Risk-of-Bias Tool (ROB 2). Data were extracted using a predefined table, including outcomes such as pain, quadriceps muscle strength, 30-s sit-to-stand test (30STS) and Timed Up and Go test (TUG).

Result

Ten studies were included in the meta-analysis. The pooled results indicated that, compared to conventional resistance training, LL-BFRT significantly improved knee joint pain [SMD = 0.25, 95%CI (0.02, 0.48), P = 0.03], increased quadriceps muscle strength [SMD = 0.46, 95%CI (0.04, 0.88), P = 0.03], and enhanced performance on the 30s sit-to-stand test (30STS) [WMD = 1.71, 95%CI (0.30, 3.11), P = 0.02]. However, no significant difference was observed in the improvement of the Timed Up and Go test (TUG) [WMD = -0.13, 95%CI (-0.51, 0.24), P = 0.49]. Subgroup analysis revealed that interventions with an occlusion pressure >100 mmHg and a duration ≤6 weeks had a significant impact on pain relief, quadriceps muscle strength, and the 30STS performance. For patients with KOA aged >65 years, LL-BFRT was more effective in alleviating pain, while for patients aged ≤65 years, it demonstrated more significant improvements in quadriceps strength and 30STS performance.

Conclusion

Limited evidence suggests that LL-BFRT may be more effective than conventional resistance training in improving pain, quadriceps muscle strength, and 30STS performance in patients with KOA, while exhibiting a comparable effect on TUG test.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/#myprospero, identifier CRD42024603542.

Non-Pharmacological Pain Management for Osteoarthritis: Review Update

PURPOSE OF REVIEW

To summarize the state of research and recent studies on non-pharmacological therapies for osteoarthritis (OA).

RECENT FINDINGS

High intensity interval training is an exercise-based intervention with some new, promising findings for people with OA. Among mind-body therapies, Tai Chi has the strongest evidence base to date. Diet + exercise has the strongest evidence for weight management in OA, with recent research focusing on maintenance of weight loss and non-calorie restrictive dietary patterns. Among psychological interventions, Cognitive Behavioral Therapy has the strongest evidence base, with some support for Acceptance and Commitment Therapy and mindfulness-based interventions. There is a clear role for non-pharmacological therapies for OA. Future research should address the effectiveness of interventions for which evidence is still limited, strategies for maintenance, heterogeneity of patients' responses to these therapies, and implementation in clinical and community settings.

Vascular occlusion for optimising the functional improvement in patients with knee osteoarthritis: a randomised controlled trial

OBJECTIVES

Knee osteoarthritis (KOA) is a leading cause of global disability with conventional exercise yielding only modest improvements. Here we aimed to investigate the benefits of integrating blood flow restriction (BFR) into traditional exercise programmes to enhance treatment outcomes.

METHODS

The Vascular Occlusion for optimizing the Functional Improvement in patients with Knee Osteoarthritis randomised controlled trial enrolled 120 patients with KOA at Ghent University Hospital, randomly assigning them to either a traditional exercise programme or a BFR-enhanced programme over 24 sessions in 12 weeks. Assessments were conducted at baseline, 6 weeks, 12 weeks and 3 months postintervention using linear mixed models with Dunn-Sidak corrections for multiple comparisons. Primary outcome was the Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaire at 3 months follow-up with knee strength, Pain Catastrophizing Scale questionnaire and functional tests as secondary outcomes. Analysis followed an intention-to-treat approach (NCT04996680).

RESULTS

The BFR group showed greater improvements in KOOS pain subscale (effect size (ES)=0.58; p=0.0009), quadriceps strength (ES=0.81; p<0.0001) and functional tests compared with the control group at 12 weeks. At 3 months follow-up, the BFR group continued to exhibit superior improvements in KOOS pain (ES=0.55; p=0.0008), symptoms (ES=0.59; p=0.0004) and quality of life (QoL) (ES=0.66; p=0.0001) with sustained benefits in secondary outcomes. Drop-out rates were similar in both groups.

CONCLUSION

Incorporating BFR into traditional exercise programmes significantly enhances short-term and long-term outcomes for patients with KOA demonstrating persistent improvements in pain, symptoms, QoL and functional measures compared with conventional exercise alone. These findings suggest that BFR can provide the metabolic stimulus needed to achieve muscle strength and functional gains with lower mechanical loads. Reduced pain and increased strength support a more active lifestyle, potentially maintaining muscle mass, functionality and QoL even beyond the supervised intervention period.

TRIAL REGISTRATION NUMBER

NCT04996680.

Credibility of Blood Flow Restriction Training in Patients With Knee Osteoarthritis: A Systematic Review and Meta-analysis

Background

The effectiveness and practicality of blood flow restriction training (BFRT) as a nonsurgical intervention for treating patients with knee injuries are uncertain because of the small size of BFRT trials and inconsistent results.

Purpose

To conduct a meta-analysis comparing the effectiveness of BFRT versus traditional resistance training in patients with knee osteoarthritis (OA) in terms of pain, muscle strength, functional performance, self-reported function, muscle size, and adverse events during exercise.

Study Design

Systematic review; Level of evidence: 1.

Methods

Under the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, we searched the Web of Science, PubMed, EMBASE, and other databases for randomized controlled trials of BFRT interventions in patients with knee OA. Methodological and quality evaluations, heterogeneity analysis, and subgroup analysis of the included studies were conducted, and effect sizes were evaluated using mean differences or standardized mean differences (SMDs). Subgroup and sensitivity analyses were used to explore the sources of heterogeneity.

Results

Of 2826 initial studies, 6 studies (N = 228 patients) were included. The results of the meta-analysis indicated that compared with resistance training, BFRT did not significantly affect pain relief (SMD, -0.02 [95% CI, -0.30 to 0.26]; P = .88), muscle strength (SMD, 0.32 [95% CI, -0.33 to 0.96]; P = .33), functional performance (SMD, 0.25 [95% CI, -0.29 to 0.80]; P = .36), or self-reported function (SMD, -0.252 [95% CI, -0.88 to 0.45]; P = .52). However, BFRT reduced the risk of adverse events (risk ratio, 0.45 [95% CI, 0.20 to 1.01]; P = .05). Subgroup analysis revealed that compared with low-load resistance training, BFRT significantly increased muscle size (SMD, 0.88 [95% CI, 0.09 to 1.68]; P = .02). The quality-of-evidence assessment indicated that the evidence level for the above outcomes was low and that the strength of the recommendation was weak.

Conclusion

The results of our meta-analysis indicated that compared with resistance training, BFRT did not significantly improve symptom outcomes in patients with knee OA. It is important to acknowledge that the findings were limited by the small number of studies and sample sizes that were included.

Blood flow restriction combined with resistance training on muscle strength and thickness improvement in young adults: a systematic review, meta-analysis, and meta-regression

BACKGROUND

High-intensity resistance training is known to be the most effective method for enhancing muscle strength and thickness, but it carries potential injury risks. Blood flow restriction (BFR) combined with resistance training has been proposed as a safer alternative method for improving muscle strength and thickness.

METHODS

A meta-analysis was conducted, including 20 studies from five databases that met the inclusion criteria, to assess the efficacy of BFR combined with resistance training compared to traditional resistance training (NOBFR). The analysis focused on changes in muscle strength and thickness. Subgroup analysis and meta-regression were performed to explore the effects of tourniquet width and pressure.

RESULTS

The findings showed that BFR combined with resistance training is comparable to traditional resistance training in enhancing muscle strength [0.11, 95%CI: (-0.08 to 0.29), I 2 = 0%] and muscle thickness [-0.07, 95% CI: (-0.25 to 0.12), I 2 = 0%]. Subgroup analysis indicated no significant differences in muscle strength (P = 0.66) and thickness (P = 0.87) between low-intensity BFR training and other intensity levels. Meta-regression suggested that tourniquet width and pressure might affect intervention outcomes, although the effects were not statistically significant (P > 0.05).

CONCLUSION

BFR combined with resistance training offers a viable alternative to high-intensity resistance training with reduced injury risks. We recommend interventions of 2-3 sessions per week at 20%-40% of 1 RM, using a wider cuff and applying an arterial occlusion pressure of 50%-80% to potentially enhance muscle strength and thickness. It is also recommended to release tourniquet pressure during rest intervals to alleviate discomfort. This protocol effectively improves muscle strength with minimal cardiac workload and reduced risk of adverse events.

SYSTEMATIC REVIEW REGISTRATION

[https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023495465], identifier [CRD42023495465].

Comparative Efficacy of Various Exercise Therapies and Combined Treatments on Inflammatory Biomarkers and Morphological Measures of Skeletal Muscle among Older Adults with Knee Osteoarthritis: A Network Meta-Analysis

Osteoarthritis is associated with high risks of sarcopenia in older populations. Exercise interventions are promising treatments for musculoskeletal impairments in knee osteoarthritis (KOA). The purpose of this study was to identify the comparative effects of exercise monotherapy and its adjunct treatments on muscle volume and serum inflammation for older individuals with KOA. A literature search in the electronic databases was comprehensively performed from this study's inception until April 2024 to identify relevant randomized controlled trials (RCTs) that reported muscle morphology and inflammation outcomes after exercise. The included RCTs were analyzed through a frequentist network meta-analysis (NMA). The standard mean difference (SMD) with a 95% confidence interval was estimated for treatment effects on muscle morphology and inflammation biomarkers. The relative effects on each main outcome among all treatment arms were compared using surface under the cumulative ranking (SUCRA) scores. The certainty of evidence (CoE) was assessed by the GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) ranking system. Probable moderators of the treatment efficacy were investigated by network meta-regression analysis. This study included 52 RCTs (4255 patients) for NMA. Among the 27 identified treatment arms, isokinetic training plus physical modality as well as low-load resistance training plus blood-flow restriction yielded the most optimal treatment for inflammation reduction (-1.89; SUCRA = 0.97; CoE = high) and muscle hypertrophy (SMD = 1.28; SUCRA = 0.94; CoE = high). The patient's age (β = -0.73), the intervention time (β = -0.45), and the follow-up duration (β = -0.47) were identified as significant determinants of treatment efficacy on muscle hypertrophy. Exercise therapy in combination with noninvasive agents exert additional effects on inflammation reduction and muscle hypertrophy compared to its corresponding monotherapies for the KOA population. However, such treatment efficacy is likely moderated by the patient's age, the intervention time, and the follow-up duration.

Validity and reliability of a wearable blood flow restriction training device for arterial occlusion pressure assessment

PURPOSE

The blood flow restriction (BFR) training is an effective approach to promoting muscle strength, muscle hypertrophy, and regulating the peripheral vascular system. It is recommended to use to the percentage of individual arterial occlusion pressure (AOP) to ensure safety and effectiveness. The gold standard method for assessing arterial occlusive disease is typically measured using Doppler ultrasound. However, its high cost and limited accessibility restrict its use in clinical and practical applications. A novel wearable BFR training device (Airbands) with automatic AOP assessment provides an alternative solution. This study aims to examine the reliability and validity of the wearable BFR training device.

METHODS

Ninety-two participants (46 female and 46 male) were recruited for this study. Participants were positioned in the supine position with the wearable BFR training device placed on the proximal portion of the right thigh. AOP was measured automatically by the software program and manually by gradually increasing the pressure until the pulse was no longer detected by color Doppler ultrasound, respectively. Validity, inter-rater reliability, and test-retest reliability were assessed by intraclass correlation coefficients (ICC) and Bland-Altman analysis.

RESULTS

The wearable BFR training device demonstrated good validity (ICC = 0.85, mean difference = 4.1 ± 13.8 mmHg [95% CI: -23.0 to 31.2]), excellent inter-rater reliability (ICC = 0.97, mean difference = -1.4 ± 6.7 mmHg [95% CI: -14.4 to 11.7]), and excellent test-retest reliability (ICC = 0.94, mean difference = 0.6 ± 8.6 mmHg [95% CI: -16.3 to 17.5]) for the assessment of AOP. These results were robust in both male and female subgroups.

CONCLUSION

The wearable BFR training device can be used as a valid and reliable tool to assess the AOP of the lower limb in the supine position during BFR training.

Blood flow restriction training improves the efficacy of routine intervention in patients with chronic ankle instability

As a new means of rehabilitation, blood flow restriction training (BFRT) is widely used in the field of musculoskeletal rehabilitation. To observe whether BFRT can improve the efficacy of routine rehabilitation intervention in patients with chronic ankle instability (CAI). Twenty-three patients with CAI were randomly divided into a routine rehabilitation group (RR Group) and a routine rehabilitation ​+ ​blood flow restriction training group (RR ​+ ​BFRT Group) according to the Cumberland Ankle Instability Tool (CAIT) score. The RR Group was treated with routine rehabilitation means for intervention, and the RR ​+ ​BFRT Group was treated with a tourniquet to restrict lower limb blood flow for rehabilitation training based on routine training. Before and after the intervention, the CAIT score on the affected side, standing time on one leg with eyes closed, comprehensive scores of the Y-balance test, and surface electromyography data of tibialis anterior (TA) and peroneus longus (PL) were collected to evaluate the recovery of the subjects. Patients were followed up 1 year after the intervention. After 4 weeks of intervention, the RR ​+ ​BFRT Group CAIT score was significantly higher than the RR Group (19.33 VS 16.73, p ​< ​0.05), the time of standing on one leg with eyes closed and the comprehensive score of Y-balance were improved, but there was no statistical difference between groups (p ​> ​0.05). RR ​+ ​BFRT Group increased the muscle activation of the TA with maximum exertion of the ankle dorsal extensor (p ​< ​0.05) and had no significant change in the muscle activation of the PL with maximum exertion of the ankle valgus (p ​> ​0.05). There was no significant difference in the incidence of resprains within 1 year between the groups (36.36% VS 16.67%, p ​> ​0.05). The incidence of ankle pain in the RR ​+ ​BFRT Group was lower than that in the RR Group (63.64% VS 9.09%, p ​< ​0.01). Therefore, four-weeks BFRT improves the effect of the routine intervention, and BFRT-related interventions are recommended for CAI patients with severe ankle muscle mass impairment or severe pain.

Intermittent blood flow restriction with low-load resistance training for older adults with knee osteoarthritis: a randomized, controlled, non-inferiority trial protocol

BACKGROUND

Knee osteoarthritis (KOA) is a chronic musculoskeletal disorder characterized by pain and functional impairment. Blood flow restriction (BFR) with low-load resistance training (LLRT) demonstrates a similar improvement in clinical outcomes to high-load resistance training (HLRT) in treating KOA. It has not been established whether intermittent blood flow restriction (iBFR) with LLRT can lead to clinical outcomes that are comparable to those produced by continuous blood flow restriction (cBFR) with LLRT and HLRT. The aim of the proposed study is to evaluate the efficacy of iBFR with LLRT on pain, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), muscle strength, muscle mass, physical function, perceptions of discomfort and effort, and adherence in KOA patients.

METHODS

This is a three-arm, non-inferiority, randomized controlled trial utilizing blinded assessors. Two hundred thirteen participants will be randomly allocated to one of the following three groups: iBFR group-receiving 4 months of LLRT with iBFR, twice weekly (n = 71); cBFR group-receiving 4 months of LLRT with cBFR, twice weekly (n = 71); or HLRT group-receiving 4 months of HLRT without BFR, twice weekly (n = 71). The primary outcome is pain. The secondary outcomes include the WOMAC, muscle strength, muscle mass, physical function, perceptions of discomfort and effort, and adherence. Pain and WOMAC will be measured at the baseline and 4 and 12 months after randomizations. Muscle strength, muscle mass, and physical function will be measured at the baseline and 4 months after randomizations. The perceptions of discomfort and effort will be measured during the first and final sessions.

DISCUSSION

BFR with LLRT has a similar improvement in clinical outcomes as HLRT. However, cBFR may cause elevated ratings of perceived exertion and local discomfort, compromising patient tolerability and treatment adherence. If iBFR with LLRT could produce improvement in clinical outcomes analogous to those of HLRT and iBFR with LLRT, it could be considered an alternative approach for treating patients with KOA.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2300072820. Registered on June 26, 2023.

Rehabilitation interventions in osteoarthritis

The goals of the management of osteoarthritis (OA) are to relieve joint pain and stiffness, maintain or increase joint mobility and stability, improve activities and participation, and enhance quality of life. The first step in the management is to make a comprehensive holistic assessment to understand the impact of the disease on the individual. Then, an individualized management plan can be set via a shared-decision making process between the patient and the clinician taking into account all components of functioning affected by the disease. Rehabilitation interventions serve as the basis of OA management whereas pharmacological modalities are usually administered for additional symptom control. This study aimed to overview the rehabilitation interventions used for people with OA with an update of the recent evidence. First, core management approaches that include patient education, physical activity and exercises, and weight loss were addressed; then adjunctive treatments including biomechanical interventions (e.g. orthoses, assistive devices) and physical modalities were overviewed.

Osteoarthritis year in review 2022: rehabilitation

This year in review presents key highlights from research relating to osteoarthritis (OA) rehabilitation published from the 1^st April 2021 to the 18^th March 2022. To identify studies for inclusion in the review, an electronic database search was carried out in Medline, Embase and CINAHLplus. Following screening, included studies were grouped according to their predominant topic area, including core OA rehabilitation treatments (education, exercise, weight loss), adjunctive treatments, novel and emerging treatments or research methods, and translation of rehabilitation evidence into practice. Studies of perceived high clinical importance, quality, or controversy in the field were selected for inclusion in the review. Headline findings include: the positive role of technology to support remote delivery of core OA rehabilitation treatments, the importance of delivering educational interventions alongside exercise, the clinical and cost-effectiveness of a stepped approach to exercise, controversy around the potential mechanisms of action of exercise, mixed findings regarding the use of splinting for thumb base OA, increasing research on blood flow restriction training as a potential new intervention for OA, and evidence that the beneficial effects from core OA treatments seen in randomised controlled trials can be seen when implemented in clinical practice. A consistent finding across several recently published systematic reviews is that randomised controlled trials testing OA rehabilitation interventions are often small, with some risk of bias. Whilst future research is warranted, it needs to be large scale and robust, to enable definitive answers to important remaining questions in the field of OA rehabilitation.

Effectiveness of Blood Flow Restriction in Neurological Disorders: A Systematic Review

There is scientific evidence that Blood Flow Restriction (BFR) is beneficial in healthy people, the elderly and patients with musculoskeletal disorders. A systematic review was conducted to evaluate the effectiveness of BFR in patients with neurological disorders. The literature search was conducted up until July 2022 in the following databases: PubMed, Web of Science (WOS), Physiotherapy Evidence Database (PEDro), LILACS, Scopus, Cumulative Index of Nursing and Allied Literature Complete (CINAHL), the Cochrane Library and Scientific Electronic Library Online (SciELO). The PEDro scale was used to analyze the methodological quality of the studies, and the Cochrane Collaboration's tool was employed to evaluate the risk of bias. A total of seven articles were included. BFR seems to be beneficial in neurological disorders. Improvements have been found in sensorimotor function, frequency and step length symmetry, perceived exertion, heart rate and gait speed, walking endurance, fatigue, quality of life, muscles thickness, gluteus density and muscle edema. No improvements were found in lower limb strength or balance. However, results must be taken with caution due to the small number of articles and to the large heterogeneity. More clinical trials are needed. These studies should homogenize the protocols used in larger samples, as well as improve their methodological quality.

Effect of low-load resistance training with different degrees of blood flow restriction in patients with knee osteoarthritis: study protocol for a randomized trial

BACKGROUND

Knee osteoarthritis (KOA) is a common degenerative disease that causes pain, functional impairment, and reduced quality of life. Resistance training is considered as an effective approach to reduce the risk of muscle weakness in patients with KOA. Blood flow restriction (BFR) with low-load resistance training has better clinical outcomes than low-load resistance training alone. However, the degree of BFR which works more effectively with low-load resistance training has not been determined. The purpose of this study is to evaluate the effectiveness of different degrees of BFR with low-load resistance training in patients with KOA on pain, self-reported function, physical function performance, muscle strength, muscle thickness, and quality of life.

METHODS

This is a study protocol for a randomized, controlled trial with blinded participants. One hundred individuals will be indiscriminately assigned into the following groups: two training groups with a BFR at 40% and 80% limb occlusion pressure (LOP), a training group without BFR, and a health education group. The three intervention groups will perform strength training for the quadriceps muscles twice a week for 12 weeks, while the health education group will attend sessions once a week for 12 weeks. The primary outcome is pain. The secondary outcomes include self-reported function, physical function performance, muscle strength of the knee extensors, muscle mass of the quadriceps, quality of life, and adverse events. Intention-to-treat analysis will be conducted for individuals who withdraw during the trial.

DISCUSSION

Previous studies have shown that BFR with low-load resistance training is more effective than low-load resistance training alone; however, a high degree of BFR may cause discomfort during training. If a 40% LOP for BFR could produce similar clinical outcomes as an 80% LOP for BFR, resistance training with a low degree of BFR can be chosen for patients with KOA who are unbearable for a high degree of BFR.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2000037859 ( http://www.chictr.org.cn/edit.aspx?pid=59956&htm=4 ). Registered on 2 September 2020.