Normal Values of Regional Bone Density within the Foot for Community Dwelling Caucasian Women in the US

Osteoporosis (OP) is a major public health threat for 44 million Americans, sixty-eight percent of which are women. Foot and ankle providers can play an important role in OP detection by identifying at-risk patients and referring them on for formal bone densitometry testing early. The aim of this study was to establish age-related normal values for several indices which are commonly used to describe bone mineral density in the foot using a high risk population. Radiographs of 180 healthy, Caucasian females (ages 20-79, stratified by decade) attending a large Chicago-area outpatient podiatry clinic from 1998 to 2005 were randomly selected and retrospectively reviewed. The lesser metatarsals on anterior-posterior (AP) foot radiographs were evaluated for combined cortical thickness (CCT), percent cortical area (PCA), and for the presence of prominent primary trabeculations (PPT) and intracortical striations (IS). The calcaneus was evaluated using Jhamaria's Calcaneal Index on lateral radiographs. There were 139 patients with the full compliment of radiographic and chart data. All indices were found to be sensitive to the effects of aging (p<0.05) and all demonstrated acceptable inter- and intra-rater reliability (e.g., moderate to excellent agreement or CV less than 0.10). Establishing a set of normal values and ranges for pedal radiographic indices of bone density may help foot and ankle providers to better identify women at risk for osteoporosis and osteoporotic fracture. These radiographic norms may also have value in the pre-operative assessment of bone quality in surgical patients.