Better Knee, Better Me™: effectiveness of two scalable health care interventions supporting self-management for knee osteoarthritis – protocol for a randomized controlled trial

BACKGROUND: Although education, exercise, and weight loss are recommended for management of knee osteoarthritis, the additional benefits of incorporating weight loss strategies into exercise interventions have not been well investigated. The aim of this study is to compare, in a private health insurance setting, the clinical- and cost-effectiveness of a remotely-delivered, evidence- and theory-informed, behaviour change intervention targeting exercise and self-management (Exercise intervention), with the same intervention plus active weight management (Exercise plus weight management intervention), and with an information-only control group for people with knee osteoarthritis who are overweight or obese. METHODS: Three-arm, pragmatic parallel-design randomised controlled trial involving 415 people aged ≥45 and ≤ 80 years, with body mass index ≥28 kg/m(2) and < 41 kg/m(2) and painful knee osteoarthritis. Recruitment is Australia-wide amongst Medibank private health insurance members. All three groups receive access to a bespoke website containing information about osteoarthritis and self-management. Participants in the Exercise group also receive six consultations with a physiotherapist via videoconferencing over 6 months, including prescription of a strengthening exercise and physical activity program, advice about management, and additional educational resources. The Exercise plus weight management group receive six consultations with a dietitian via videoconferencing over 6 months, which include a very low calorie ketogenic diet with meal replacements and resources to support behaviour change, in addition to the interventions of the Exercise group. Outcomes are measured at baseline, 6 and 12 months. Primary outcomes are self-reported knee pain and physical function at 6 months. Secondary outcomes include weight, physical activity levels, quality of life, global rating of change, satisfaction with care, knee surgery and/or appointments with an orthopaedic surgeon, and willingness to undergo surgery. Additional measures include adherence, adverse events, self-efficacy, and perceived usefulness of intervention components. Cost-effectiveness of each intervention will also be assessed. DISCUSSION: This pragmatic study will determine whether a scalable remotely-delivered service combining weight management with exercise is more effective than a service with exercise alone, and with both compared to an information-only control group. Findings will inform development and implementation of future remotely-delivered services for people with knee osteoarthritis. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN12618000930280 (01/06/2018).