Hind‐ and midfoot bone morphology varies with foot type and sex

Abstract

Foot type has been associated with pain, injury, and altered gait mechanics. Morphological variations in foot bones due to foot type variation may impact surgical and therapeutic treatments. The purpose of this study was to utilize principal component analysis (PCA) to determine how morphology of the hind‐ and midfoot bones differs among foot types and sex. The calcaneus, talus, navicular, and cuboid were segmented using previously obtained computed tomography (CT) scans and converted to surface models. The CTs were sorted into four foot types—cavus, neutrally aligned, asymptomatic planus, and symptomatic planus. Morphometric shape analysis software (Geomorph) was used to perform a PCA to determine which components varied between foot types and between sexes. The calcaneus showed planus feet of both types to have calcanei that have decreased height and increased length compared to neutrally aligned feet. The talus demonstrated increased posterior mass for cavus feet compared to neutrally aligned feet. For the navicular, symptomatic planus had a more posteriorly positioned tuberosity and were wider than asymptomatic planus feet. The cuboid did not exhibit any differences between foot types. Sex differences, found only at the talus and navicular, were subtle. PCA is an objective technique that helped elucidate differences in bone morphology between foot types and sex without needing to determine the features of interest before comparing groups. Understanding these variations can help inform diagnosis of foot pathologies and surgical protocols as well as improve computer models of the foot. Published 2018. This article is a U.S. Government work and is in the public domain in the USA. J Orthop Res 9999:1–16, 2019.

Bilateral Symmetry, Sex Differences, and Primary Shape Factors in Ankle and Hindfoot Bone Morphology

“…We described this variability as a change in the slope of the talar neck. Our results for primary shape factors in the calcaneus were very similar to previous reports 16,27 indicating mode 1 was related to the length and height of the calcaneus, mode 2 was related to differences in the inclination of the sustentaculum tali or height and width, and mode 3 was related to differences in the talar articulating surfaces (mode 3 for Tümer et al 27 ). It is important to consider the analysis methods in SSM analysis when comparing results among studies.…”

“…Contrary to our hypothesis, the male and female tali were similar in size, whereas the calcaneus in females was overall longer but thinner than in males. A recent study by Moore et al 16 employed SSM to identify sex-dependent differences in the talus, calcaneus, cuboid, and navicular. Contrary to our results, they identified subtle differences between male and female tali, and reported no sex differences in the calcaneus.…”

“…However, our study sample size (20 subjects, 40 total ankles) was similar to previous SSM studies involving ankle and hindfoot bones. 13,14,16,27 Melinska et al 14 generated 18 bilateral calcanei models using 28 subjects and, in a subsequent study, 15 bilateral models of the cuboid, navicular, and talus using 30 subjects. Those studies, however, did not include bilateral scans from the same individual and instead age-matched left- and right-sided bones.…”

“…11,25 Early research investigating sex-dependent differences in ankle bone morphology focused on discrete anatomic features. 13,14,16,27,29 More recently, statistical shape modeling 16 or principal components analysis 27 has been performed to identify independent variations in ankle bone shape. Those studies were somewhat contradictory, with one study identifying male-female differences in the tibia, calcaneus, and talus 27 and the other reporting only that sex differences in ankle bones were subtle.…”

Sex- and age-related variations in the three-dimensional orientations and curvatures of the articular surfaces of the human talus

“…Sex differences in the navicular articular surface of the talus have been reported by Ferrari et al [17], who indicated that the female navicular articular surface of the talus was more twisted in the frontal plane and more curved than that in males. In contrast, a recent geometric morphometric studies [18][19][20] has not detected sex differences in the articular surface orientation of the talus. Hence, based on these previous studies, the sex-and age-related differences in the articular morphology of the talus are still under debate.…”