Effects of blood flow restriction training in patients with knee osteoarthritis: A meta- analysis

Background. Knee osteoarthritis (KOA) is a common degenerative disease.Resistance training is considered as an effective approach to reduce the risk of muscle weakness in patients with KOA. Blood flow restriction training (BFRT) with low-load resistance training has better clinical outcomes than low-load resistance training alone. However, the degree of BFRT which works more effectively withlow-load resistance training has not been determined. The purpose of this study is to provide a comprehensive overview of the existing data regarding the impact of blood flow restriction training (BFRT) on quadriceps strength, muscle size, pain, physical function, biomarkers, quality of life, and adverse events in patients with KOA. Method. A comprehensive search was conducted in five English-language electronic databases to identify randomized controlled trials (RCTs) comparing BFRT with conventional resistance training in patients with KOA. The selection of studies was based on predetermined inclusion and exclusion criteria. The methodological quality and evidence quality of the selected studies were evaluated. The retrieval period for the literature was from the creation of the database to June 2023. Results. A total of six RCTs were included in this meta-analysis, examining the effects of BFRT compared with those of conventional resistance training on KOA. The pooled results indicated a significant difference between the BFRT group and the control group in terms of quadriceps strength (SMD 0.39 (95% CI 0.18, 0.60), p = 0.01) and biomarkers (SMD 1.31 (95% CI 0.73, p = 0.00). However, BFRT did not show a significant difference compared to conventional resistance training in muscle size (ES = −0.47 (95% CI −1.51, 0.58), p = 0.45), pain (SMD −0.02, (95% CI −0.29, 0.25), p = 0.88), physical function (ES −0.09 (95% CI −0.37, 0.20), p = 0.14), quality of life (SMD 0.30 (95% CI −0.13, 0.73), p = 0.30) or adverse events (RR 0.45 (95% CI 0.20, 1.01), p = 0.05). Conclusions. The evidence reviewed suggests that BFRT may be beneficial for improving muscle strength and biomarkers compared to control training, but it may not be more effective in treating other symptoms of patients with osteoarthritis of the knee, including those related to muscle size, pain, physical function, quality of life, and adverse events. More high-quality evidence is needed to further investigate its therapeutic effects.