Surgical treatment of depression fractures of the lateral tibial plateau using porous titanium granules

The clinical and radiological results were excellent in this pilot study of four cases of depression fracture of the lateral tibial plateau, where, in addition to internal fixation with screws or a buttress plate, porous titanium granules were used to support the elevated articular surface.     

Life-style and different fracture prevalence: A cross-sectional comparative population-based study

Summary In order to explain the higher prevalence of fractures in urban compared with rural areas, 782 residents in the city of Malmö, Sweden and 486 inhabitants from the nearby rural municipality of Sjöbo were invited to participate in an sex- and age-matched cross-sectional study on life-style differences; 73 and 80% respectively responded. Responders answered a questionnaire on medical and social background and were interviewed on past and present physical activity. The men and women of the rural area were found to be significantly more active physically at work and during spare time. Housing was larger in the rural area. For women, these differences are decreasing in the younger age groups. Bone mass was found to be correlated to heavier work load for men. Other life-style variable such as dairy calcium intake, coffee drinking, estrogen medication, and morbidity, could not explain this difference. Higher prevalence of fractures in the city could therefore be explained by physicall less active life-style.     

Mathematical relationships between bone density and mechanical properties: a literature review

BACKGROUND: In many published studies, elastic properties of bone are correlated to the bone density, in order to derive an empirical elasticity-density relationship. The most common use of these relationships is the prediction of the bone local properties from medical imaging data in subject-specific numerical simulation studies. The proposed relationships are substantially different one from the other. It is unclear whether such differences in elasticity-density relationships can be entirely explained in terms of methodological discrepancies among studies. METHODS: All relevant literature was reviewed. Only elasticity-density relationships derived from similarly controlled experiments were included and properly normalized. The resulting relationships were grouped according to the most important methodological differences: type of end support during testing, specimen geometry, and anatomical sampling location. FINDINGS: Even after normalization with respect to strain rate and densitometric measurement unit, substantial inter-study differences do exist, and they can only be partially explained by the methodological differences between studies. INTERPRETATION: Some recommendations are made for the application of elasticity-density relationships to subject-specific finite element studies. The importance of defining a standardized mechanical testing methodology for bone specimens is stressed, and some guidelines that emerged from the literature are proposed. To identify density-elasticity relationships suitable for use in subject-specific FE studies, the development of a benchmark study is also proposed, where the elasticity-density relationship is taken as the variable under study, and a numerical model of known numerical accuracy predicts experimental strain measurements.     

A modified method for assigning material properties to FE models of bones

The aim of the present study is to compare the results from subject-specific finite element analysis (FEA) of a human femur to experimental measurements, using two different methods for assigning material properties to the FE models. A modified material mapping strategy allowing for spatial variation of material properties within the elements and Young's modulus surface corrections is presented and compared to a more conventional strategy, whereby constant material properties are assigned to each element. The accuracy of the superficial stress–strain predictions was evaluated against experimental results from 13 strain gauges and five different load cases. Both methods predicted stresses with acceptable accuracy (R² = 0.92, root mean square error, RMSE < 10%), with the conventional method performing slightly better. The modified method performed better in strain prediction (R² = 0.85, RMSE = 23% versus R² = 0.79, RMSE = 31%).     

Bioactive molecules from the Blue Lagoon: in vitro and in vivo assessment of silica mud and microalgae extracts for their effects on skin barrier function and prevention of skin ageing

Abstract:  Bathing in the Blue Lagoon, a specific geothermal biotope in Iceland has been known for many years to be beneficial for human skin in general and for patients with psoriasis and atopic dermatitis in particular. The scientific rationale for this empirical observation, however has remained elusive. We now report that extracts prepared from silica mud and two different microalgae species derived from the Blue Lagoon are capable of inducing involucrin, loricrin, transglutaminase-1 and filaggrin gene expression in primary human epidermal keratinocytes. The same extracts also affects primary human dermal fibroblasts, because extracts from silica mud and one type of algae inhibited UVA radiation-induced upregulation of matrix metalloproteinase-1 expression and both algae, as well as silica mud extracts induced collagen 1A1 and 1A2 gene expression in this cell type. These effects were not restricted to the in vitro situation because topical treatment of healthy human skin ( n  = 20) with a galenic formulation containing all three extracts induced identical gene regulatory effects in vivo , which were associated with a significant reduction of transepidermal water loss. In aggregate, these results suggest that the bioactives in Blue Lagoon have the capacity to improve skin barrier function and to prevent premature skin ageing. These observations explain at least some of the beneficial effects of bathing in the Blue Lagoon and provide a scientific basis for the use of Blue Lagoon extracts in cosmetic and/or medical products.