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.