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

Abstract

ObjectiveTo compare radiographic measures of foot structure between people with and without symptomatic radiographic midfoot osteoarthritis (OA).MethodsThis was a cross‐sectional study of adults aged ≥50 years registered with four UK general practices who reported foot pain in the past year. Bilateral weightbearing dorsoplantar and lateral radiographs were obtained. Symptomatic radiographic midfoot OA was defined as midfoot pain in the last four weeks, combined with radiographic OA in one or more midfoot joints (first cuneometatarsal, second cuneometatarsal, navicular‐first cuneiform and talonavicular). Midfoot OA cases were matched 1:1 for sex and age to controls with a five‐year age tolerance. Eleven radiographic measures were extracted and compared between the groups using independent samples t‐tests and effect sizes (Cohen's d).ResultsWe identified 63 midfoot OA cases (mean age 66.8, SD 8.0, 32 males, 31 females) and matched these to 63 controls (mean age 65.9, SD 7.8). There were no differences in metatarsal lengths between the groups. However, those with midfoot OA had a higher calcaneal first metatarsal angle (d=0.43, small effect size, p=0.018) and lower calcaneal inclination angle (d=0.46, small effect size, p=0.011) compared with controls.ConclusionsPeople with midfoot OA have a flatter foot posture compared with controls. Although caution is required when inferring causation from cross‐sectional data, these findings are consistent with a pathomechanical pathway linking foot structure to the development of midfoot OA. Prospective studies are required to determine the temporal relationships between foot structure, function, and the development of this common and disabling condition.image