Efficacy of low-load blood flow restricted resistance EXercise in patients with Knee osteoarthritis scheduled for total knee replacement (EXKnee): protocol for a multicentre randomised controlled trial

Abstract

IntroductionUp to 20% of patients undergoing total knee replacement (TKR) surgery report no or suboptimal pain relief after TKR. Moreover, despite chances of recovering to preoperative functional levels, patients receiving TKR have demonstrated persistent deficits in quadriceps strength and functional performance compared with healthy age-matched adults. We intend to examine if low-load blood flow restricted exercise (BFRE) is an effective preoperative method to increase functional capacity, lower limb muscle strength and self-reported outcomes after TKR. In addition, the study aims to investigate to which extent preoperative BFRE will protect against surgery-related atrophy 3 months after TKR.MethodsIn this multicentre, randomised controlled and assessor blinded trial, 84 patients scheduled for TKR will be randomised to receive usual care and 8 weeks of preoperative BFRE or to follow usual care-only. Data will be collected before randomisation, 3–4 days prior to TKR, 6 weeks, 3 months and 12 months after TKR. Primary outcome will be the change in 30 s chair stand test from baseline to 3-month follow-up. Key secondary outcomes will be timed up and go, 40 me fast-paced walk test, isometric knee extensor and flexor strength, patient-reported outcome and selected myofiber properties.Intention-to-treat principle and per-protocol analyses will be conducted. A one-way analysis of variance model will be used to analyse between group mean changes. Preintervention-to-postintervention comparisons will be analysed using a mixed linear model. Also, paired Student’s t-test will be performed to gain insight into the potential pretraining-to-post-training differences within the respective training or control groups and regression analysis will be used for analysation of associations between selected outcomes.Ethical approvalThe trial has been accepted by the Central Denmark Region Committee on Biomedical Research Ethics (Journal No 10-72-19-19) and the Danish Data Protection Agency (Journal No 652164). All results will be published in international peer-reviewed scientific journals regardless of positive, negative or inconclusive results.Trial registration numberNCT04081493.

The pathophysiological effects of exercise in the management of idiopathic inflammatory myopathies: A scoping review

“…The results support the notion that low‐load exercise has no risk of intensified inflammatory activity 39 . Low‐load blood‐flow restriction exercise might be beneficial in preventing/delaying myositis‐related decline in muscle contractile capacity without imposing a high magnitude of mechanical strain on muscles and with no exacerbation of the disease 40,41 . The potential mechanisms underlying this positive effect of low‐load blood‐flow restriction exercise include boosted muscle fiber recruitment, overproduction of hormones, and increased muscle protein synthesis as a response to diminished blood flow 41 …”

“…A trial in patients with sporadic inclusion body myositis examined the effects of 12 weeks of low‐load blood‐flow restriction exercise on immune and inflammatory responses 39 . The protocol comprised unilateral leg press, knee extension, knee flexion (introduced from the 4th week), calf raise, and dorsiflexion 40 . Muscle biopsies from tibialis anterior/vastus lateralis revealed an increase in myocellular infiltration of CD3 − CD8 + ‐expressing natural killer cells following blood‐flow restriction exercise, which is consistent with an amplified immune response.…”

The Evolution of Blood Flow Restricted Exercise

“…It is also worthwhile noting that the benefits associated with low-load BFR exercise are not limited to healthy young individuals ( Abe et al, 2010a ), but also middle-aged and elderly ( Karabulut et al, 2010 ; Abe et al, 2010b ; Ozaki et al, 2011b ). Moreover, several studies have demonstrated the benefits of BFR training to clinical populations, such as post-surgery rehabilitating athletes ( Kilgas et al, 2019 ) and individuals dealing with different forms of chronic inflammation and pain (i.e., arthritis, chronic fatigue syndrome, and fibromyalgia; McCully et al, 2004 ; Korakakis et al, 2018 ; Jørgensen et al, 2020 ). Thus, low-intensity aerobic exercise combined with BFR or low-load resistance exercise with BFR has emerged as potential training alternatives to traditional aerobic and resistance training programs, which are commonly performed at high intensities or using heavy loads, making it difficult for many of the populations already mentioned to withstand the training demands.…”

Effects of Low-Load Blood-Flow Restricted Resistance Training on Functional Capacity and Patient-Reported Outcome in a Young Male Suffering From Reactive Arthritis

“…During the last decade, research on resistance training with loads as low as 20% of 1RM with concurrent partial or complete blood flow restriction to the exercising limb (low-load blood-flow restricted resistance training: BFR-RT) has consistently proven to promote skeletal muscle hypertrophy and increase muscle strength comparable to that of HRTS (Wernbom et al, 2008 ; Hughes et al, 2017 ; Grønfeldt et al, 2020 ). The ability to promote muscle morphological and muscle mechanical adaptations with low loads makes BFR-RT very interesting in clinical rehabilitation (Hughes et al, 2017 ; Jørgensen et al, 2018 , 2020 ; Petersson et al, 2020 ). Furthermore, BFR-RT is safe in both cardiac and orthopedic patient populations and leads to greater reduction in knee joint swelling (Hughes et al, 2017 , 2019 ; Groennebaek et al, 2019 ; Patterson et al, 2019 ; Jørgensen et al, 2020 ).…”

“…The ability to promote muscle morphological and muscle mechanical adaptations with low loads makes BFR-RT very interesting in clinical rehabilitation (Hughes et al, 2017 ; Jørgensen et al, 2018 , 2020 ; Petersson et al, 2020 ). Furthermore, BFR-RT is safe in both cardiac and orthopedic patient populations and leads to greater reduction in knee joint swelling (Hughes et al, 2017 , 2019 ; Groennebaek et al, 2019 ; Patterson et al, 2019 ; Jørgensen et al, 2020 ). Results from our research group have demonstrated that patients can administer BFR exercises safely and correctly with minimal supervision (Petersson et al, 2020 , Høghsholt et al, under review).…”