Quantitative relationship of first metatarsophalangeal head morphology to hallux rigidus and hallux valgus

Abstract

BackgroundPrevious qualitative studies have linked first metatarsal head morphology with hallux valgus (HV) and hallux rigidus (HR). This study used a quantitative measurement of 1st MT radius of curvature to assess if HR MT heads were flatter than HV heads. MethodsWeight bearing foot films were used in HV, HR, and normal patients (no forefoot complaints) to measure the metatarsal head radius of curvature (normalized by dividing the radius of curvature by the first metatarsal length to adjust for magnification and foot size). ResultsRadiographs from 299 feet were analyzed (105 normal, 57 HR, and 137 HV). The mean normalized radius of curvature was smaller in HV than HR, with normal feet in between (p<.05 for all comparisons). Metatarsal head curvature did not vary with age, weight, or BMI. ConclusionThese quantitative measurements are consistent with qualitative observations, validating the use of subjective metatarsal head morphology assessments.