Despite its clinical relevance in the context of ankle fractures, little is known about the bone microarchitecture and strength of the distal fibula, especially regarding age-, sex-, and subregion-specific effects. To address this gap of knowledge, we obtained fibulae from 30 skeletally intact donors at autopsy (each 15 male and female), which were analyzed by high-resolution peripheral quantitative computed tomography including micro-finite element analysis. Scans were performed in a 7-cm volume of interest and evaluated in three subregions according to the Danis-Weber fracture classification. Group comparisons and linear regression analyses were applied to evaluate the effects of age, sex, and subregion. From distal to proximal, we observed an increase of cortical parameters and a decrease of trabecular parameters. Age was primarily associated with a cortical decrease in all subregions (Danis-Weber type A, B, and C) in women. While women showed a greater magnitude of decline, men also exhibited an age-associated decrease for some parameters, including cortical area and cortical thickness in the type C subregion.Stiffness and failure load were highest in the type C subregion in both women and men. A critical age-related decline in bone strength parameters in the type B subregion was observed in women, providing an explanation for the increased incidence of low-traumatic type B fractures in the elderly. Together, these findings extend the current understanding of distal fibular microarchitecture, likely explaining the epidemiologic features of distal fibula fractures and emphasizing the need for age-adapted treatment algorithms.

Background: Several fibula-based reconstruction techniques have been introduced to address ligamentous injuries of the posterolateral corner of the knee. These techniques involve a drill tunnel with auto- or allograft placement through the proximal fibula. Purpose: To determine the skeletal microarchitecture of the proximal fibula and its association with age and to compare the microarchitecture within the regions of different drill tunnel techniques for reconstruction of the posterolateral corner. Study Design: Descriptive laboratory study. Methods: A total of 30 human fibulae were analyzed in this cadaveric imaging study. High-resolution peripheral quantitative computed tomography measurements were performed in a 4.5 cm–long volume of interest at the proximal fibula. Three-dimensional microarchitectural data sets of cortical and trabecular compartments were evaluated using customized scripts. The quadrants representing the entry and exit drill tunnel positions corresponding to anatomic techniques (LaPrade/Arciero) and the Larson technique were analyzed. Linear regression models and group comparisons were applied. Results: Trabecular microarchitecture parameters declined significantly with age in women but not men. Analysis of subregions with respect to height revealed stable cortical and decreasing trabecular values from proximal to distal in both sexes. Along with a structural variability in axial slices, superior values were found for the densitometric and microarchitectural parameters corresponding to the fibular drill tunnels in the anatomic versus Larson technique (mean ± SD; bone volume to tissue volume at the entry position, 0.273 ± 0.079 vs 0.175 ± 0.063; P < .0001; cortical thickness at the entry position, 0.501 ± 0.138 vs 0.353 ± 0.081 mm; P < .0001). Conclusion: Age represented a relevant risk factor for impaired skeletal microarchitecture in the proximal fibula in women but not men. The region of drill tunnels according to anatomic techniques showed superior bone microarchitecture versus that according to the Larson technique.