Effectiveness of Blood Flow Restriction Exercise Therapy to Reduce Pain in Knee Osteoarthritis Patients (BFR;OA)

Effectiveness of Blood Flow Restriction Exercise Therapy to Reduce Pain in Knee Osteoarthritis Patients

Effectiveness of Blood Flow Restriction (BFR) Exercise Therapy to Reduce Pain in Knee Osteoarthritis (OA) Patients. A Double-blinded Randomised Clinical Trial

Resistance training of knee extensor muscles is being used in physiotherapy management in knee osteoarthritis (OA) to improve pain and physical function. Blood flow restriction (BFR) has been suggested to improve pain and increase muscle strength in healthy subjects and certain diseases. Although there are clinical studies suggesting improvements in knee osteoarthritis symptoms after 4-12 weeks of exercise with BFR, the acute effects of the intervention have not been known. This study aims to assess the effectiveness of low load exercise therapy combined with BFR on acute pain reduction and within 24 hours post-intervention on people with knee OA compared to a placebo group. This study will take place in Athens, Greece, as part of the postgraduate MSc program of the Physiotherapy department of the University of West Attica.

A double-blinded randomised clinical trial with a total of 42 participants will be randomly assigned to the intervention (n=21) or the control group (n=21). The intervention group will complete a single exercise session with BFR 80%, 30% 1RM, while the control group will have sham BFR, 30% 1RM. Pain Pressure Threshold (PPT) will be assessed with the use of a digital pressure dynamometer.

Exercise: Bilateral knee extension at range 90ο-0ο Load: 30% 1RM BFR: Yes, 80% at both legs Sets: 4 Reps: 30-15-15-15 Rest: 30'' between sets Tempo: 2-0-2-0 Participants of the intervention group will receive an exercise protocol with blood flow restriction once and will be measured for changes in PPT by the use of a digital dynamometer. Exercise protocol will be four sets of bilateral knee extension 90ο-0ο, reps per set 30-15-15-15, tempo 2-0-2-0 and rest 30 sec between sets. In order to determine the training load 30% of 1RM, participants will perform bilateral knee extension in range 90ο-0ο with pain-free maximum resistance. The derived 1RM will be used to determine the 30% 1RM load. Blood flow restriction will be applied at 80% by using pressure cuffs. The cuffs will be applied to the proximal thigh. Cuff pressure needed for a 100% vascular occlusion will be determined for each individual at a seated and relaxed position.

Exercise: Bilateral knee extension at range 90ο-0ο Load: 30% 1RM BFR: Yes, Sham BFR, 10mm Hg at both legs Sets: 4 Reps: 30-15-15-15 Rest: 30'' between sets Tempo: 2-0-2-0 Participants of the control group will receive an exercise protocol with sham blood flow restriction once and will be measured for changes in PPT by the use of a digital dynamometer. Exercise protocol will be four sets of bilateral knee extension 90ο-0ο, reps per set 30-15-15-15, tempo 2-0-2-0 and rest 30 sec between sets. In order to determine the training load 30% of 1RM, participants will perform bilateral knee extension in range 90ο-0ο with pain-free maximum resistance. The derived 1RM will be used to determine the 30% 1RM load. Sham technique for blood flow restriction will be applied by using pressure cuffs inflated at 10mm Hg. The cuffs will be applied to the proximal thigh. Cuff pressure will be applied for each individual at a seated and relaxed position.

DAP is correlating VAS/NRS pain reporting scales with the functional test of 30-second Chair Stand Test (30s-CST)

30s-CST is a functional assessment evaluating leg strength and dynamic balance, the more repetitions one can do during the 30'', the better the outcome

Change of pain score from baseline with the use of reporting scales Visual Analogue Scale (VAS) / Numeric Rating Scale (NRS)

Pain reporting scales as NRS are using 0-10 grades to measure how big the pain is, 10 is for the worst pain

Greek version of DN4 will be used diagnostically to identify the existence of neuropathic pain, a score greater than 4/10 suggests the existence of neuropathic pain

Greek version of the KOOS will be used diagnostically to identify the severity of the disease. Each category score ranges 0-100, the minimum score is the worst

1RM will be used diagnostically to identify the maximum strength of the participants. Each participant will extend their knees bilaterally, pain-free, 90o-0ο with the maximum weight

Recording of demographics and medical notes will be used to identify the inclusion and exclusion criteria

Inclusion Criteria: Current osteoarthritis clinical diagnosis according to either European League Against Rheumatism (EULAR) or American College of Rheumatology (ACR) criteria VAS/NRS Knee pain ≥3/10 during activity Exclusion Criteria: Previous experience with BFR Has followed knee exercise or kinesiotherapy program in the past 3 months New medicines in the past 3 months Any lower limb surgery in the past 6 months Knee arthroplasty surgery (Knee replacement) Any active healing process affecting walking (fracture, sprain, strain, etc.) Diagnosed with rheumatologic/neurologic disease affecting functionality Diagnosed or history of heart or vascular diseases Diagnosed with respiratory/metabolic disease Personal history of cancer Cognitive problems Pregnancy (only for female participants) Any other indication not to participate in exercise