Authors (including presenting author) :
Chan VWK(1), Yeung SS(2), Chan PK(1), Fu H(1), Cheung MH(1), Cheung A(1), Luk M(1), Tsang CCR(2), Chiu KY(1)
Affiliation :
(1) Department of Orthopaedic and Traumatology, Queen Mary Hospital
(2) Department of Physiotherapy, MacLehose Medical Rehabilitation Center
Introduction :
Knee osteoarthritis (KOA) is one of the most common causes of disability, causing pain, weakness, and function loss. Quadricep strength is a crucial factor in the occurrence, progression, and physical function in a patient with KOA. Although high-intensity training (HIT) increases muscle strength and mass, such high resistance is poorly tolerated in patients with advanced KOA.
Recent research found that combining low-intensity training (LIT) with blood flow restriction (BFR) effectively improves muscle strength. However, its use and application in advanced KOA are unclear. Hence, we designed this randomized controlled study to investigate the effect of BFR training on quadriceps strength and physical function in patients with advanced KOA.
Objectives :
Aim to investigate the effect of BFR training on quadriceps strength and physical function in patients with advanced KOA.
Methodology :
We performed a randomized controlled study on patients with advanced KOA. We recruited those on the waiting list for arthroplasty, Kellegran-Lawrence grading of >=3, and consent to participate. We excluded those with peripheral vascular or cardiovascular diseases, a history of deep vein thrombosis, and restricted knee range of movement (ROM) (> 10 degrees fixed flexion contracture and flexion less than 90 degrees).
Physical parameters and one maximum repetition (1-RM) was assessed at baseline. Patients were randomized to the control or BFR group. All received two sessions per week for eight weeks. For the control, LIT with leg press (LP) and knee extension (KE) at 20-30% of 1-RM (4 sets, 30 repetitions for the first set, and 15 repetitions for the rest) was done at each session. For the BFR group, the same training with the addition of 70% limb occlusion while exercising.
Physical assessments, including 1-RM, ROM, visual analog pain scale (VAS, 0-10), timed up and go (TUG), and 30second timed stand test (TSS), were performed up to 12th weeks. Training load was adjusted in the 4th week according to the re-assessment 1-RM. Oxford Knee Score (OKS) and Knee Injury Osteoarthritis Outcome Score (KOOS) was charted at the 8th week. Assessor for all outcomes are blinded to the treatment received.
Power analysis based on previous meta-analysis showed that 23 patients is required in each group for 80% power. Repeated-measures t-test was performed for continuous parameters. Continuous variables are presented in means and standard deviations (SD), while qualitative variables are presented in percentages. P-value
Result & Outcome :
Twenty-one patients, 14 in control and 12 in the BFR group, were analyzed. All baseline parameters, including gender, BMI, knee pain and range, quadriceps power, and functional scores, were comparable (p< 0.05).
Concerning quadricep power, the BFR group had a significant increase in KE power from their baseline in the 4th, 8th, and 12th week (9.7kg (SD 4.2), 10.8kg (SD 5.4), 12.4kg (SD 6.1), p< 0.05), while the control group only showed an improvement in the 12th week (10.9kg (SD 6.1), p< 0.05). BFR group showed a significant increase in LP power from the 4th to 12th weeks (28.1kg (SD 11.7), 30.83kg (SD 13.4), 32.72kg (SD 12.9), p< 0.05), while the LP power improved in the control group in the 8th and 12th week (26.5kg (SD 9.1), 28.9kg (SD 10.1), p< 0.05). There was a significant difference in the percentage improvement in KE power between the two groups from 4th to 12th weeks (46.7kg vs 11.1kg, 77.3kg vs 20.3kg, 105.3kg vs 21.0kg, p< 0.05), while no differences in LP power.
Concerning functional assessments, BFR group had a significant improvement in TSS at 12th weeks (15.7 (SD 5.5), p< 0.05), while both groups showed no significant change in TUG test
No between or within-group difference in VAS, ROM, OKS, and KOOS.
All patients tolerated the training with no dropouts or adverse events.
