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Background: Tibial shaft fractures are usually treated by interlocking nails or plates. The ideal implant choice depends on many variables. Aim: To assess the mechanical behavior of interlocking nails and plates in the treatment of closed comminuted midshaft fractures of the tibia using finite element analysis. Material and methods: This is a prospective study of 50 patients with a mean age of 28.4 years with closed comminuted fractures of the midshaft of the tibia. Data evaluation was done by Finite element analysis (FEA). Fixation was revised in two cases. Results: After load application, there were significant differences in both bending (P = 0.041) and strain percent (P = 0.017), reflecting that interlocking nails were superior to plates. There were also significant differences between titanium and stainless-steel materials in bending (p = 0.041) and strain percent (p = 0.017) after applying load, indicating that titanium was superior to stainless steel. Conclusion: Interlocking nails are superior to plates in treating midshaft tibial fractures. The use of blocking screws may be needed in interlocking nails depending on the pattern and extension of the fracture.

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Abstract: The present study was undertaken to elucidate the cellular mechanisms, which govern metal sequestration and detoxification in gastropods. For this purpose the pond snail, Lymnaea stagnalis was exposed to environmentally relevant concentrations of three species of metals (Al, Zn and Cd) for 30 days and the localization and fate of these metals were followed in different tissues of the snails. The measurement of relative distribution of metals between tissues revealed that the digestive gland and kidney account for most of the accumulated metals. Al and Cd (non-essential metals) were redistributed to the digestive gland, possibly because of the presence of specific binding entities in the digestive glands of the herein species. This study focuses on the role of intracellular metal-containing granules on metal sequestration. Three main types of granules were identified in the digestive gland cells namely small, green and yellow granules. The morphological examination and the progressive accumulation of elements within these granules revealed that they are developmental stages with the yellow granule being the mature one. The total number of these granules was found to be significantly increased upon exposure of the snails to Al only. This increase may be a response to the large amount of Al that is accumulated through feeding route of this grazing snail. X-ray microanalysis (XRMA) revealed that metals were localized in all three types of digestive gland granules. The increased amount of ligands (P and S) in the granules may give evidence for their role in metal sequestration. Levels of Al and P were positively correlated in the digestive gland granules. It is possible that aluminium is bound to phosphorus to render it insoluble and so to both immobilize it within the lysosome and to be excreted in a highly insoluble form. On the other hand, both Zn and Cd induced marked upregulation of S in mature (yellow) granules by 26- and 11-folds, respectively. The lysosomal codeposition of S and either Cd or Zn in the lysosomal granules in addition to the increase in RER cisternae may indicate that the exposure to these metals could induce metallothionein synthesis in the cells. The microscopical examinations in the present study revealed that metal detoxification from the digestive gland cells may occur via faeces or via basal exocytosis towards hemocytes dispersed by the connective tissue in the visceral mass. In the kidney, one type of granules, the excretory concretions, was identified in the nephrocytes. The significant increase in the number of these concretions in the snail L. stagnalis upon exposure to metals may give further evidence for their role in metal excretion. [Copyright &y& Elsevier]