Blood Flow Restriction Training After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

BACKGROUND

Anterior cruciate ligament reconstruction (ACLR) is frequently followed by significant quadriceps atrophy and strength loss due to postoperative pain and the necessity for low-load rehabilitation. Blood flow restriction (BFR) training is an emerging modality that may facilitate muscle strength and hypertrophy under low-load conditions, but its efficacy for improving functional outcomes after ACLR remains to be conclusively determined.

PURPOSE: To systematically evaluate the effects of BFR training on lower limb function, quadriceps strength, and knee pain in patients following ACLR.

STUDY

DESIGN

Systematic review; Level of evidence, 3.

METHODS

A comprehensive literature search was conducted in PubMed, Embase, Cochrane Library, Web of Science, PEDro, EBSCO and CNKI for randomized controlled trials (RCTs) published between January 2015 and August 2025. A total of 606 records were identified through database searching, and 9 RCTs were included after screening. Data on functional scores (Lysholm, International Knee Documentation Committee [IKDC]), quadriceps peak torque (PT), pain (visual analog scale [VAS]), and range of motion (ROM) were extracted and analyzed using RevMan 5.4, and risk of bias was assessed using the Cochrane tool. Meta-analyses were performed using weighted mean differences (WMDs) with fixed- or random-effects models as appropriate, and heterogeneity was assessed using the I 2 statistic.

RESULTS

Nine RCTs involving 372 participants were included. Meta-analysis revealed that BFR training significantly improved Lysholm scores (WMD, 5.75; 95% CI, 0.60-10.90; P = .03) and quadriceps PT (WMD, 8.34; 95% CI, 7.47-9.22; P < .00001), and increased total work output (P = .006). However, no significant differences were observed in IKDC scores, VAS pain scores, or ROM (P > .05). Sensitivity analyses confirmed the robustness of the primary findings.

CONCLUSION

Our study demonstrated that BFR training may promote early recovery of quadriceps strength and selected aspects of knee function after ACLR under low-load conditions. BFR appears feasible and generally well tolerated in the included trials; however, safety conclusions are limited by inconsistent adverse-event reporting. Its effects on pain relief, joint mobility, and long-term functional recovery require further investigation.