[Translated article] Comparative clinical and biomechanical study of different types of osteosynthesis in the treatment of distal femur fractures.

Introduction And Objectives: Distal femoral fractures represent a problem due to their high number of complications. The aim was to compare the results, complications and stability achieved with retrograde intramedullary nailing and the angular stable plate in the treatment of distal femoral diaphyseal fractures.

Material And Method: A clinical and experimental biomechanical study was carried out using finite elements.

Comparative clinical and biomechanical study of different types of osteosynthesis in the treatment of distal femur fractures.

Introduction And Objectives: Distal femoral fractures represent a problem due to their high number of complications. The aim was to compare the results, complications and stability achieved with retrograde intramedullary nailing and the angular stable plate in the treatment of distal femoral diaphyseal fractures.

Material And Method: A clinical and experimental biomechanical study was carried out using finite elements.

Influence of plate size and screw distribution on the biomechanical behaviour of osteosynthesis by means of lateral plates in femoral fractures.

Distal femoral fractures are fractures associated with high rates of morbidity and mortality, affecting to three different groups of individuals: younger people suffering high-energy trauma, elderly people with fragile bones and people with periprosthetic fractures around previous total knee arthroplasty. They have been classically treated with conventional plates and intramedullary nails and more recently with locked plates that have increased their indications to more types of fractures. The main objective of the present work is the biomechanical study, by means of finite element simulation, of the stability achieved in the osteosynthesis of femoral fractures in zones 4 and 5 of Wiss, by using locked plates with different plate lengths and different screw configurations, and analysing the effect of screw proximity to the fracture site.

Biomechanical behavior of retrograde intramedullary nails in distal femoral fractures.

Fractures of the distal femur affect three different groups of individuals: younger people suffering high-energy trauma, elderly people with fragile bones and people with periprosthetic fractures around previous total knee arthroplasty. Main indications of intramedullary nailing are for supracondylar fractures type A or type C of the AO classification. The main objective of the present work is to analyze, by means of FE simulation, the influence of retrograde nail length, considering different blocking configurations and fracture gaps, on the biomechanical behavior of supracondylar fractures of A type.

Probabilistic assessment of fatigue initiation data on highly crosslinked ultrahigh molecular weight polyethylenes.

Ultrahigh molecular weight polyethylenes (UHMWPE) showing wear resistance, oxidative stability and good mechanical performance go on being a relevant research area in biomaterials for total joint replacements, where fatigue happens to be a recurrent damage mode that needs to be investigated. While crack propagation lifetime has been extensively studied, fatigue initiation data are scarcely offered in the literature, often due to the higher costs implied in the experimental programs. Moreover, their analysis is not always suitable to obtain reliable guidance.

Effect of Nitinol surface treatments on its physico-chemical properties.

The main purpose of this work is the study of different physicochemical treatments on Nitinol slabs and wires, with the aim of inducing the formation of a TiO(2) surface film capable of increasing the corrosion resistance of the material and of reducing the release of Ni when the Nitinol samples were immersed in simulated body fluid (SBF). To this end, a battery of measurements (surface roughness, contact angle, electrochemical corrosion, chemical analysis as a function of depth, and Ni release to SBF) has been used to characterize Nitinol commercial samples, as received, and also after the different treatments performed. The results clearly indicate the effectiveness of the passivation TiO(2) layer as a barrier against Ni leaching, and the detrimental effects of any processes (such as polishing or cutting) that result in exposure of areas not coated by the TiO(2) film.

Mechanical comparative analysis of stents for colorectal obstruction.

The goal of this work is the mechanical comparison of different types of stents for colorectal obstructions. We consider self-expanding and balloon-expanding stents made of two different materials such as stainless steel and shape memory NiTi alloy. The mechanical parameters are expansion rate, shortening, radial compression resistance, longitudinal and perimetral adaptability, and buckling resistance.

Design, manufacture and evaluation of a NiTi stent for colon obstruction.

We have designed, manufactured and evaluated a prototype of a new stent based on the superelasticity of the NiTi alloy for colon obstruction, which is the first clinical manifestation of colorectal cancer in up to 29% of cases. The stent is auto-expandable diamond cell type, manufactured from a NiTi tube with 4.5 mm in diameter, in which longitudinal grooves were performed by cutting laser technique.

Fractography evolution in accelerated aging of UHMWPE after gamma irradiation in air.

We studied the fracture surface evolution of ultra high molecular weight polyethylene (UHMWPE) specimens, manufactured from GUR 1050 compression moulded sheets, after gamma sterilisation in air followed by different aging times after thermal treatment at 120 degrees C. Degradation profiles were obtained by FTIR and DSC measurements after 0, 7, 14, 24 and 36h aging. We observed by SEM the morphology patterns at these aging times, in surface fractographies after uniaxial tensile test of standardised samples.