Effects of blood flow restriction exercise interventions on patellofemoral pain syndrome: a systematic review and meta-analysis

Abstract

Purpose – Previous studies suggest that blood flow restriction training (BFRT) may improve pain and knee function in individuals with patellofemoral pain syndrome (PFPS); however, its additional clinical benefit compared with general rehabilitation exercise (GRE) remains uncertain. This study aimed to compare the effects of BFRT and GRE in PFPS rehabilitation through a systematic review and meta-analysis. Methods – The Cochrane Library, PubMed, Web of Science, PEDro, Scopus, and ScienceDirect were searched up to February 14, 2026 (CRD420261296172). Interventional studies comparing BFRT with GRE in exercise-based rehabilitation for PFPS were included. Outcomes included pain intensity, self-reported knee function, knee extensor strength, and quadriceps morphology. Results – Thirteen studies were included qualitatively, and 11 randomized controlled trials involving 508 participants were included in the meta-analysis. BFRT produced immediate reductions in pain during functional tasks, including shallow single-leg squat (MD = 2.13; P < 0.00001), deep single-leg squat (MD = 2.38; P < 0.00001), and step-down tasks (MD = 2.05; P < 0.00001). This short-term analgesic effect remained significant 45 minutes after exercise. Over longer-term follow-up, BFRT showed a modest benefit for overall pain (SMD = 0.37; P = 0.0005) and knee extensor strength (SMD = 0.28; P = 0.01) compared with GRE. However, self-reported knee function did not differ significantly between groups (MD = 1.93; P = 0.12). Evidence for quadriceps morphology was limited, and no clear between-group difference was observed (SMD = 0.30; P = 0.24). Conclusion – In PFPS rehabilitation, BFRT may provide clinically relevant benefits for short-term pain reduction during functional tasks and modest improvements in knee extensor strength. However, current evidence does not show a clear advantage for self-reported knee function or quadriceps morphological outcomes. These findings should be interpreted cautiously because of protocol heterogeneity and limited long-term evidence. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/view/CRD420261296172, identifier CRD420261296172.