The relationship between the distal metatarsal articular angle and intersesamoidal crista: An osteological study

Background As hallux valgus (HV) progresses, the first metatarsal drifts medially and the subsequent lateral drift of the sesamoids results in intersesamoidal crista erosion. This study aimed to provide a novel method of assessing crista erosion and determine if there is a relationship between that erosion and an increase in the distal metatarsal articular angle (DMAA). Methods The DMAA and size of the intersesamoidal crista was measured on the first metatarsals of 120 adult modern human individuals. There was an equitable spread of both sexes, a wide age range (18–88 years), from three South African population groups (Zulu, Sotho, “European”). The following non-metric features were observed: intersesamoidal crista appearance, metatarsal head shape, and first intermetatarsal facet. Correlation tests, t-tests and Analyses of Variance (ANOVA) were used to determine relationships between variables. Results The Pearson correlation test showed no significant correlation between the DMAA and crista ratio (r = 0.092, p = 0.154, α = 0.05). DMAA: there was a significant difference between sides (p = 0.009), right side larger; there was a significant difference between Zulu and “European” samples (p = 0.036) but not between “Europeans” and Sotho (p = 0.270); and there was a slight positive correlation with an increase in age. Crista: there was a significant difference between the sexes (p = 0.044), with females having less erosion. Conclusions There is no significant relationship between the DMAA and crista erosion. Severe cartilaginous erosion is present before osteological changes occur, and the unexpected result may be reflected in skeletal specimens in which no cartilaginous changes can be observed. A novel, experimental method of assessing HV in modern human skeletal material is proposed.