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.