Biomedizinische Technik. Biomedical engineering最新文献

The prevalence of obesity, a worldwide health problem, is increasing. Obesity or overweight has significant effects, especially on lower limb biomechanics. Previous studies have investigated the biomechanical effects of weight gain on the knee and hip joints. These studies have been conducted on different individuals with normal weight and overweight. However, no investigation has been carried out between women and men in terms of weight gain. Females usually gain weight in the gluteal-femoral region, whereas males gain weight in the abdominal region. Due to this difference, it is thought that the effects of weight gain should be examined in a gender-specific manner. In this study, a link-segment model of the lower limb was created. Then the sit-to-stand movement was simulated according to female and male-specific weight gain scenarios. According to these results, weight gain in the abdominal region (men-specific) increases the ankle and knee joint moments more than weight gain in the gluteal-femoral region (women-specific). In obese scenarios for males and females, while the ankle and knee joint moment increases, the hip joint moment decreases. These results would be beneficial for considering biomechanical differences caused by gender-specific weight gain in rehabilitation processes and orthotic and prosthetic designs.

In order to prevent failure as well as ensure comfort, patient-specific modelling for prostheses has been gaining interest. However, deterministic analyses have been widely used in the design process without considering any variation/uncertainties related to the design parameters of such prostheses. Therefore, this study aims to compare the performance of patient-specific anatomic Total Knee Arthroplasty (TKA) with off-the-shelf TKA. In the patient-specific model, the femoral condyle curves were considered in the femoral component's inner and outer surface design. The tibial component was designed to completely cover the tibia cutting surface. In vitro experiments were conducted to compare these two models in terms of loosening of the components. A probabilistic approach based on the finite element method was also used to compute the probability of failure of both models. According to the deterministic analysis results, 103.10 and 21.67 MPa von Mises stress values were obtained for the femoral component and cement in the anatomical model, while these values were 175.86 and 25.76 MPa, respectively, for the conventional model. In order to predict loosening damage due to local osteolysis or stress shield, it was determined that the deformation values in the examined cement structures were 15% lower in the anatomical model. According to probabilistic analysis results, it was observed that the probability of encountering an extreme value for the anatomical model is far less than that of the conventional model. This indicates that the anatomical model is safer than the conventional model, considering the failure scenarios in this study.

Due to the presence of electric fields and piezoelectricity in various living tissues, piezoelectric materials have been incorporated into biomedical applications especially for tissue regeneration. The piezoelectric scaffolds can perfectly mimic the environment of natural tissues. The ability of scaffolds which have been made from piezoelectric materials in promoting cell proliferation and regeneration of damaged tissues has encouraged researchers in biomedical areas to work on various piezoelectric materials for fabricating tissue engineering scaffolds. In this review article, the way that cells of different tissues like cardio, bone, cartilage, bladder, nerve, skin, tendon, and ligament respond to electric fields and the mechanism of tissue regeneration with the help of piezoelectric effect will be discussed. Furthermore, all of the piezoelectric materials are not suitable for biomedical applications even if they have high piezoelectricity since other properties such as biocompatibility are vital. Seen in this light, the proper piezoelectric materials which are approved for biomedical applications are mentioned. Totally, the present review introduces the recent materials and technologies that have been used for tissue engineering besides the role of electric fields in living tissues.