Use of magnesium implants is a new trend in orthopedic research because it has several important properties that recommend it as an excellent resorbable biomaterial for implants. In this study, the corrosion rate and behavior of magnesium alloys during the biodegradation process were determined by in vitro assays, evolution of hydrogen release, and weight loss, and further by in vivo assays (implantation in rabbits’ bone and muscle tissue). In these tests, we also used imaging assessments and histological examination of different tissue types near explants. In our study, we analyzed the Mg-1Ca alloy and all the hypotheses regarding the toxic effects found in in vitro studies from the literature and those from this in vitro study were rejected by the data obtained by the in vivo study. Thus, the Mg-1Ca alloy represents a promising solution for orthopedic surgery at the present time, being able to find applicability in the small bones: hand or foot.

The aim of this study is to observe the time of mixing influence on the properties of commercially available PMMA bone cement, widely used in cranioplasty. The studied bone cement is provided in the form of a solid powder (the copolymer) and a liquid monomer. The increase of the mixing phase duration and the use of two mixing methods (manual and mechanical) effect on surface and mechanical characteristics were studied. The samples were prepared as if in the operation room. Surface characteristics were studied by means of contact angle measurements, morphology by scanning electron microscopy (SEM) and mechanical characteristics determined by flexural tests in a three point bending configuration. The conclusion of this study is that by using a mechanical mixing method and increasing mixing time higher flexural strength can be achieved by reducing pore content within bone cement.

The immersed components of hydroelectric power plants are permanently in contact with the water stream and their wear occurs by corrosion, erosion and cavitation. This damage is usually repaired by welding: the procedure is fast and reduces plant downtime. Adopting proper weld procedures are crucial for blade performance and to establish a protocol the following experiment was devised: rectangular samples 600x200x15mm were obtained from a discarded blade used in a hydroelectric power plant and in the median region a 3mm deep groove was milled to simulate erosion damage. The damage was repaired by welding using MIG, WIG, MMAW and oxyacetylene techniques using 136L as filler on cold and preheated at 400�C base materials. Specimens from the welded ensembles were obtained and prepared accordingly for corrosion testing. Post corrosion testing studies using the light microscope and scanning electron microscope were performed in order to determine surface damage. At first glance results appear contradictory: the corrosion test results revealed best behavior for MIG weld repairs, on the cold sample, while the corrosion features measured on the exposed area revealed that oxyacetylene welding would be best. Complementary methods are required and currently employed to establish optimum welding procedure parameters for water turbine blade repairs.

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Several techniques are used to reconstruct the anterior cruciate ligaments (ACL) by using different grafts in order to obtain a new ligament with properties closest to those of the healthy one. Our aim was a faster graft harvesting and the integration into the bone tissue; we have studied the efficiency of the techniques that preserve the torn ligament end vs. the techniques that used a graft harvested from the patient. The ligamentoplasty studies performed on rabbits reveal a satisfactorily cost-efficiency ratio, this being the main reason for choosing this model. We wanted to study the importance of preserving one edge of the torn ligament as a base of integration for the new graft and compare the appearance of the blood vessels and the neoformation tissue in the two study groups. For the first study group we performed an implantation technique that uses a complete new graft harvested from the same animal and for the second group we used the technique which preserves the torn ligament. All the surgical procedures were conducted on the NZW rabbits. All ligamentoplasty reconstruction surgical interventions were conducted on the left limb and the graft was harvested from the extensori digitorum longi located on the lateral side of the rabbit�s thigh. Twelve rabbits in each group were operated upon using the two techniques and the results were compared. No major complications were noted, the long term results were similar, and with no significant differences as far as the ligament integration was concerned. The study group in which the ligament end was preserved showed a more rapid integration. Our study suggests that keeping a longer ligament end correlates with early graft integration.