Aims The optimal treatment of proximal fifth metatarsal (MT-V) fractures remains controversial. The most commonly used classification according to Lawrence and Botte distinguishes between three fracture types (zone I to III, from proximal to distal), aiming to derive the healing potential and treatment recommendations. It has been proposed that certain fracture types, such as zone II fractures, should be allocated to zone I and therefore treated conservatively rather than surgically based on their healing potential. Accordingly, this work aims to investigate the osseous microarchitecture in the three different zones of the proximal MT-V as a morphological basis for fracture classification. Methods A total of 30 bilateral MT-V bones were obtained from 15 skeletally intact body donors. The zone-specific, trabecular, and cortical microarchitecture at the MT-V base was analyzed by high-resolution peripheral quantitative CT (HR-pQCT). Differences between zones I, II, and III were analyzed using group comparisons and the influence of possible demographic factors using linear regression analyses. Results A decrease in trabecular bone microarchitecture with a simultaneous increase in cortical parameters was observed from zones I to III. Both trabecular and cortical parameters showed greater structural similarity between zones I and II than between zones II and III. Specifically, trabecular bone mineral density, area, and bone volume fraction, as well as cortical bone mineral density and cortical thickness, all exhibited smaller mean differences between zones I and II than between zones II and III. Female sex and advanced age were risk factors for poor microarchitecture in all three zones. Conclusion Our observations support the assumption that, due to the closer microstructural similarity, zone II fractures might have a similarly good healing potential as zone I fractures. The observed deterioration of microarchitecture in women and the elderly might indicate an increased susceptibility to fracture in this patient group. Cite this article: Bone Joint Res 2026;15(1):16–24.
Krüger et al. (Mon,) studied this question.
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