Intermittent blood flow restriction with low-load resistance training for older adults with knee osteoarthritis: a randomized, controlled, non-inferiority trial protocol

Abstract

Background: Knee osteoarthritis (KOA) is a chronic musculoskeletal disorder characterized by pain and functional impairment. Blood flow restriction (BFR) with low-load resistance training (LLRT) demonstrates a similar improvement in clinical outcomes to high-load resistance training (HLRT) in treating KOA. It has not been established whether intermittent blood flow restriction (iBFR) with LLRT can lead to clinical outcomes that are comparable to those produced by continuous blood flow restriction (cBFR) with LLRT and HLRT. The aim of the proposed study is to evaluate the efficacy of iBFR with LLRT on pain, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), muscle strength, muscle mass, physical function, perceptions of discomfort and effort, and adherence in KOA patients.

Methods: This is a three-arm, non-inferiority, randomized controlled trial utilizing blinded assessors. Two hundred thirteen participants will be randomly allocated to one of the following three groups: iBFR group-receiving 4 months of LLRT with iBFR, twice weekly (n = 71); cBFR group-receiving 4 months of LLRT with cBFR, twice weekly (n = 71); or HLRT group-receiving 4 months of HLRT without BFR, twice weekly (n = 71). The primary outcome is pain. The secondary outcomes include the WOMAC, muscle strength, muscle mass, physical function, perceptions of discomfort and effort, and adherence. Pain and WOMAC will be measured at the baseline and 4 and 12 months after randomizations. Muscle strength, muscle mass, and physical function will be measured at the baseline and 4 months after randomizations. The perceptions of discomfort and effort will be measured during the first and final sessions.

Discussion: BFR with LLRT has a similar improvement in clinical outcomes as HLRT. However, cBFR may cause elevated ratings of perceived exertion and local discomfort, compromising patient tolerability and treatment adherence. If iBFR with LLRT could produce improvement in clinical outcomes analogous to those of HLRT and iBFR with LLRT, it could be considered an alternative approach for treating patients with KOA.

Trial registration: Chinese Clinical Trial Registry ChiCTR2300072820. Registered on June 26, 2023.

Keywords: Blood flow restriction; Knee osteoarthritis; Rehabilitation; Resistance training; Vascular occlusion.

Fig. 1

Flow diagram of the planned study. KOA, knee osteoarthritis; HL, high load; iBFR, intermittent blood flow restriction; cBFR, continuous blood flow restriction

Fig. 2

Schedule of enrollment, intervention, and assessment (SPIRIT figure). HL, high load; iBFR, intermittent blood flow restriction; cBFR, continuous blood flow restriction; WOMAC, Western Ontario and McMaster Universities Osteoarthritis Index; 30sCST, 30-s chair-stand test; 40mFPWT, 40-m fast-paced walk test; TUG, timed up and go test; 6MWD, 6-min walk distance test; AEs, adverse events