The effects of blood flow restriction training on early muscle strength and mid-term knee function following anterior cruciate ligament reconstruction: a systematic review and meta-analysis

OBJECTIVE: Early restoration of muscle strength and knee joint function after anterior cruciate ligament reconstruction (ACLR) is a critical goal in the rehabilitation process. Blood flow restriction training (BFRT), a low-load training method, has gained attention in musculoskeletal rehabilitation in recent years, but its specific effects in ACLR rehabilitation remain unclear. METHODS: Relevant literature up to December 20, 2024, was searched in the PubMed, Embase, Cochrane, and Web of Science databases, and study selection was performed according to PRISMA guidelines. Randomized controlled trials (RCTs) and quasi-RCTs comparing the effects of BFRT and traditional training in ACLR rehabilitation were included. Data on early muscle strength (ACSA and MVIC) and mid-term knee function (IKDC scores and isometric strength of knee extensors) were extracted. The quality of the studies was assessed using the Cochrane risk of bias tool, and statistical analyses were conducted using fixed-effect or random-effect models. RESULTS: A total of 11 studies involving 276 patients were included, with 139 in the BFRT group and 137 in the control group. Meta-analysis showed no significant improvements in quadriceps ACSA (SMD = 0.82, 95% CI: -0.17 to 1.81, p = 0.10) or MVIC (SMD = 0.47, 95% CI: -0.16 to 1.10, p = 0.15) during the early postoperative period (≤ 3 weeks). At mid-term follow-up (8-14 weeks), BFRT significantly improved IKDC scores (SMD = 3.70, 95% CI: 0.20 to 7.21, p = 0.04). No significant differences were observed between the groups in the improvement of isometric strength of knee extensors (SMD = 0.50, 95% CI: -0.62 to 1.63, p = 0.38). CONCLUSIONS: BFRT demonstrated limited effectiveness in early muscle strength recovery during ACLR rehabilitation but may have a positive impact on mid-term knee function, particularly in improving IKDC scores. However, due to heterogeneity and potential bias in the included studies, future research should incorporate more high-quality, multicenter RCTs to further validate the mid- to long-term value of BFRT in postoperative rehabilitation.