Blood Flow Restriction Training in Knee Arthroplasty: A Systematic Review of Current Evidence on Postoperative Muscle...

Background and Objectives: Knee arthroplasty often leads to marked postoperative muscle weakness, with strength losses of up to 62% in the first month, contributing to functional impairment and patient dissatisfaction. Blood flow restriction (BFR) training, which combines low-load exercise with partial vascular occlusion, has shown promise in enhancing muscle strength across musculoskeletal conditions and may represent a valuable rehabilitation strategy for this vulnerable population. This review aimed to systematically evaluate the effectiveness and safety of BFR training in improving muscle strength and functional outcomes following knee arthroplasty. Materials and Methods: This systematic review was prospectively registered within PROSPERO (CRD420250652404) and conducted according to PRISMA guidelines. PubMed, Embase, and Cochrane Library were searched through February 2025 for randomized controlled trials (RCTs) investigating BFR training in knee arthroplasty patients. Study selection, data extraction, and risk of bias assessment (RoB 2 tool) were performed independently by two reviewers. Eligible trials reported muscle strength and/or functional outcomes as primary or secondary endpoints. Results: Four RCTs, including 148 patients undergoing total knee arthroplasty (mean age: 67 ± 6.5 years), met the inclusion criteria. All applied preoperative BFR training for 4-8 weeks with heterogeneous protocols. Two trials demonstrated significant improvements in muscle strength (1 RM leg press, 1 RM knee extension; large effect sizes) and functional outcomes (6 min walk test, 30 s sit-to-stand; earlier recovery), favoring BFR. The remaining studies showed no significant between-group differences, though moderate-to-large effect sizes generally favored BFR training. No adverse events were reported. Conclusions: Prehabilitation with BFR training shows considerable potential to enhance early postoperative muscle strength and functional recovery in patients undergoing knee arthroplasty, particularly when compared with usual care lacking structured preoperative intervention. The evidence to date suggests that BFR is a safe and well-tolerated strategy, offering an alternative for patients who cannot perform high-load resistance training. Its favorable safety profile, combined with the potential to accelerate functional recovery, highlights the promise of BFR for reducing rehabilitation costs and healthcare utilization. Nonetheless, larger, high-quality RCTs with standardized protocols and extended follow-up are required to confirm these preliminary findings and establish clear clinical guidelines for their implementation.