Effectiveness of low-load blood flow restriction training as an adjunct to conventional physiotherapy after total knee replacement: a randomised controlled trial

Background: Quadriceps weakness persists after total knee replacement (TKR), and high-load strengthening is poorly tolerated early after surgery. Low-load blood flow restriction (BFR) training may strengthen muscle with less joint loading. Objective: To compare BFR training plus conventional physiotherapy with conventional physiotherapy alone after primary unilateral TKR. Methods: In this assessor-blinded randomised controlled trial, 60 patients aged 45–75 years, 1–4 weeks after TKR, were allocated to BFR plus conventional physiotherapy (n = 30) or conventional physiotherapy alone (n = 30), three supervised sessions weekly for six to eight weeks. BFR exercise used 20–30% of one-repetition maximum at 80% limb occlusion pressure. Outcomes were isometric quadriceps strength, Timed Up and Go (TUG), Six-Minute Walk Test (6MWT) and Numeric Pain Rating Scale (NPRS). Results: All participants completed the trial, and both groups improved on every outcome (p < 0.001). The BFR group improved more in quadriceps strength (between-group difference in change 13.2 Nm; 95% CI 11.9 to 14.6), TUG (−3.7 s; −4.1 to −3.3), 6MWT (60.5 m; 53.5 to 67.5) and pain (−1.6 points; −2.3 to −1.0); all p < 0.001. No adverse events were recorded. Conclusion: Adding low-load BFR training to conventional physiotherapy after TKR produced greater shortterm gains in strength, mobility, walking endurance and pain than conventional physiotherapy alone. Larger trials with longer follow-up are needed.