Background: The prevalence of foot and ankle conditions varies among different ethnic groups. It is not known if this difference is due to any distinctive skeletal morphological characteristics of the foot. The purpose of this study was to determine if ethnic differences exist in the morphometric measurements on radiographs of the weightbearing foot.
Materials and methods: A morphometric study of weightbearing radiographs of feet was performed prospectively. Radiographic parameters were measured on digital monitors using digital tools. These were the hallux valgus angle (HVA), intermetatarsal angle (IMA), talonavicular angle (TNA), talonavicular coverage angle (TNCovA), metatarsal span (MS) on anteroposterior (AP) radiographs and talo-first metatarsal angle (T-1(st)MTA), calcaneal pitch (CP), and lateral talocalcaneal angle (LTCA) on lateral radiographs.
Results: A total of 237 feet in 126 patients (45 African Americans, 59 Caucasians, and 22 Hispanics) were studied. Statistically significant differences were found in the CP, LTCA, and MS. African Americans have significantly lower CP than Caucasians (p < 0.0001). African Americans have significantly lower CP than Hispanics (p < 0.0016). Caucasians have significantly higher TCA than African Americans (p < 0.0004). Males have a larger MS than females (p < 0.0001).
Conclusion: There are differences in the radiographic morphology of feet among different ethnic groups. A larger prospective community-based study of morphological differences is needed for better understanding of the genetic and environmental factors influencing the prevalence of foot and ankle conditions.
Clinical relevance: The clinical relevance between having a lower CP angle and a higher incidence of flat feet in African Americans warrants further investigation. It is not known if there is a relationship between posterior tibialis insufficiency and low CP.