Efficacy of arch contouring foot orthoses for midfoot osteoarthritis: Protocol for a randomised controlled trial.

Introduction: Midfoot osteoarthritis (OA) is a painful and disabling condition. Arch contouring foot orthoses have been recommended for midfoot OA, yet there is no high-quality evidence from randomised controlled trials to support their use. This clinical trial aims to evaluate the efficacy of arch contouring foot orthoses for midfoot OA.

Methods: This will be a parallel-group randomised controlled superiority trial. One-hundred and forty community-dwelling people with painful midfoot OA will be randomised to receive either arch contouring foot orthoses or flat sham inserts. Outcome measures will be obtained at baseline, 4, 8 and 12 weeks; the primary endpoint for assessing efficacy being 12 weeks. The primary outcome measure will be average midfoot pain whilst walking over the last 7 days on an 11-point numerical rating scale. Secondary outcome measures include function (walking/standing subscale of the Manchester-Oxford Foot Questionnaire), participants' perception of overall treatment effect (self-reported global rating of change on a 15-point Likert scale), physical activity (Incidental and Planned Exercise Questionnaire), general health-related quality of life (Short Form-12 Version® 2.0), use of co-interventions and adverse events.

Discussion: This trial will evaluate the efficacy of arch contouring foot orthoses for relieving pain and improving function, physical activity and health-related quality of life in people with midfoot OA. The findings will provide high-quality evidence as to whether arch contouring foot orthoses are efficacious and will help to inform clinical guidelines about the use of foot orthoses for midfoot OA.

Trial registration: Australian and New Zealand Clinical Trial Registry (ACTRN12623000953639).