Structural Foot Characteristics in People With Midfoot Osteoarthritis: Cross-Sectional Findings From the Clinical Assessment Study of the Foot

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).

Plantar pressures in people with midfoot osteoarthritis: cross-sectional findings from the Clinical Assessment Study of the Foot

BACKGROUND

Midfoot osteoarthritis (OA) is a common condition, however its aetiology is not well understood. Understanding how plantar pressures differ between people with and without midfoot OA may provide insight into the aetiology and how best to manage this condition.

RESEARCH QUESTION

To compare plantar pressures between people with and without symptomatic radiographic midfoot OA.

METHODS

This was a cross-sectional study of adults aged ≥ 50 years registered with four UK general practices who reported foot pain in the past year. Symptomatic radiographic midfoot OA was defined as midfoot pain in the last four weeks, combined with radiographic OA in one or more midfoot joints. Cases were matched 1:1 for sex and age ( ± 5 years) to controls. Peak plantar pressure and maximum force in 10 regions of the foot were determined using a pressure platform (RSscan International, Olen, Belgium) and compared between the groups using independent samples t-tests and effect sizes (Cohen's d).

RESULTS

We included 61 midfoot OA cases (mean age 67.0, SD 8.1, 31 males, 30 females) and matched these to 61 controls (mean age 66.0, SD 7.9). Midfoot OA cases displayed greater force (d=0.79, medium effect size, p = <0.001) and pressure at the midfoot (d=0.70, medium effect size, p = <0.001), greater force at the fourth metatarsophalangeal (MTP) joint (d=0.28, small effect size, p = 0.13), and fifth MTP joint (d=0.37, small effect size, p = 0.10) and greater pressure at the fifth MTP joint (d=0.34, small effect size, p = 0.13). They also displayed lower force (d=0.40, small effect size, p = 0.02) and pressure at the hallux (d=0.50, medium effect size, p = <0.001) and lower force (d=0.54, medium effect size, p = <0.001) and pressure at the lesser toes (d=0.48, small effect size, p = <0.001) compared with controls.

SIGNIFICANCE

Midfoot OA appears to be associated with lowering of the medial longitudinal arch, greater lateral push off and less propulsion at toe off. Longitudinal studies are needed to establish causal relationships.