Feasibility of a theoretically grounded, multicomponent, physiotherapy intervention aiming to promote autonomous motivation to adopt and maintain physical activity in patients with lower-limb osteoarthritis: protocol for a single-arm trial

BACKGROUND: Lower-limb osteoarthritis (OA) causes high levels of pain and disability in adults over 45 years of age. Adopting and maintaining appropriate levels of physical activity (PA) can help patients with lower-limb OA self-manage their symptoms and reduce the likelihood of developing secondary noncommunicable diseases. However, patients with lower-limb OA are less active than people without musculoskeletal pain. This single-arm feasibility trial seeks to determine the feasibility and acceptability of a complex multicomponent physiotherapy behaviour change intervention that aims to aid patients with lower-limb OA to adopt and maintain optimal levels of PA. METHODS: This trial will be conducted at one site in a National Health Service physiotherapy outpatient setting in the West Midlands of England. Up to thirty-five participants with lower-limb OA will be recruited to receive a physiotherapy intervention of six sessions that aims to optimise their PA levels during phases of behavioural change: adoption, routine formation and maintenance. The intervention is underpinned by self-determination theory (and other motivational frameworks) and seeks to foster a motivationally optimal (empowering) treatment environment and implement behaviour change techniques (BCTs) that target PA behaviours across the three phases of the intervention. Physiotherapists (n = 5–6) will receive training in the why and how of developing a more empowering motivational environment and the delivery of the intervention BCTs. Participants will complete patient-reported and performance-based outcome measures at baseline and 3-month (to reflect behavioural adoption) and 6-month (maintenance) post-baseline. Feasibility and acceptability will be primarily assessed through semi-structured interviews (purposively recruiting participants) and focus groups (inviting all physiotherapists and research staff). Further evaluation will include descriptive analysis of recruitment rates, loss of follow-up and intervention fidelity. DISCUSSION: A novel complex, multicomponent theoretical physiotherapy behaviour change intervention that aims to create a more empowering motivational treatment environment to assist patients with lower-limb OA to adopt and maintain optimal PA levels has been developed. Testing the feasibility and acceptability of the intervention and its associated physiotherapist training and related trial procedures is required to determine whether a full-scale parallel group (1:1) randomised controlled trial to evaluate the interventions effectiveness in clinical practice is indicated. TRIAL REGISTRATION: Trial register: International Standard Randomised Controlled Trial identification number: ISRCTN12002764. Date of registration: 15 February 2022. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40814-023-01274-6.