This work investigates the failure mechanism in cenosphere epoxy syntactic foams at the quasi‐static and dynamic strain rates. Split‐Hopkinson pressure bar experiments are controlled to stop dynamic deformation of the foams at various strain stages. The internal microstructure at each strain is characterized in the x‐ray microtomography and compared to the microstructure in the foams deformed quasi‐statically. The microscopic observations reveal that the failure process in syntactic foams at the low and high rates is dominated by the crushing of cenospheres and the cracking of the epoxy matrix. However, the mechanism of failure in the foam is significantly affected by the strain rate. Compared to quasi‐static compression, macro‐cracks form earlier in the matrix at dynamic rates and can propagate to split cenospheres. The volume of the damage as defined by the failure of both cenospheres and the matrix is calculated from the x‐ray microtomographic images. It is found that the damage can be quantitatively related to the strain and the strain rate using an empirical equation.

The purpose of this study was to compare the reconstructive outcomes of soft‐tissue defects around the foot and ankle with anterolateral thigh (ALT) flap or lateral supramalleolar (LSM) flap and attempt to provide an optimal strategy for elderly patients. A retrospective review of all continuous patients with foot and ankle reconstruction using different flaps from October of 2010 and October of 2020 was performed. Based on the flap types, the patients were divided into two groups: ALT flap group (n = 50) and LSM flap group (n = 46). Outcomes were assessed according to the flap survival rate, early complications, general complications, late complications, cosmetic appearance, functional outcomes and Vancouver Scar Scale (VSS). We found that there was no difference in average age, gender, aetiology, size of the defect, debridement times between the two groups; however, a significant difference in operation time, hospitalisation time and cost were noted between them. What's more, the early flap complications between them were not significantly different. The LSM flap group showed less general complications, less flap bulky and lower cosmetic appearance. Moreover, the functional evaluation and VSS seem similar (P > .05). Thus, The ALT flap and LSM flap are both flaps available for foot and ankle reconstruction in elderly patients. However, the LSM flap offers short operation time, short hospitalisation time, and less cost with a lower frequency of postoperative complications. Thus, we advocate the LSM flap for the reconstruction of moderate‐size defects of the foot and ankle region in elderly patients.