Biocompatibility is one of the mandatory requirements for the clinical use of biomaterials in orthopedics. It refers to the ability of a biomaterial to perform its function without eliciting toxic or injurious effects on biological systems but producing an appropriate host response in a specific case. Today, the biocompatibility concept includes not only bio-inertia, but also biofunctionality and biostability. High biocompatibility and functional properties are highly desirable for new biomaterials. The chemical, mechanical, structural properties of biomaterials, their interaction with biological environment or even the methodology of assessment can influence the biocompatibility. The biological evaluation of biomaterials includes a broad spectrum of in vitro and in vivo tests related to the cytocompatibility, genotoxicity, sensitization, irritation, acute and chronic toxicity, hemocompatibility, reproductive and developmental toxicitity, carcinogenicity, implantation and degradation as specified in different international standards. A brief review of the main assays used in the biocompatibility testing of orthopedic biomaterials is presented. In addition, their main biocompatibility issues are overviewed.

Bone fracture fixation uses both consecrated materials, such as metals/metal alloys, as well as synthetic materials. Synthetic materials are extremely versatile in terms of simulating biological structures, biocompatibility and, in some cases, avoid the subsequent interventions for removing the prosthetic material. Fixing an osteoporotic fracture presents major risks of failure due mainly to the bone fragility. To reduce the risk of failure, prosthetic materials have been improved with various cements. The purpose of the current study was to assess the mechanical properties of different orthopedic screws covered with a new polyurethane acrylate polymer (PUA) in order to improve the stability of the screw for the subsequent fixation of the fragility fracture. To test the efficiency of the new polymer, the breaking/fracture strength of the orthopedic screws coated with PUA was evaluated, in comparison with the screws without coating material. Our data shows that tested PUA improves the bond between the screw and bone. We estimate that the effect obtained is caused by the partial damping of the loading force due to the elastic component of the polymer.

The general opinion in the literature is that these topics remain clearly understudied and underrated, with many unknown aspects and with controversial results in the respective areas of research. Based on the previous experience of our groups regarding such matters investigated separately, here we attempt a short overview upon their links. Thus, we summarize here the current state of knowledge regarding the connections between oxidative stress and: (a) orthopedic conditions; (b) COVID-19. We also present the reciprocal interferences among them. Oxidative stress is, of course, an interesting and continuously growing area, but what exactly is the impact of COVID-19 in orthopedic patients? In the current paper we also approached some theories on how oxidative stress, metabolism involvement, and even antibiotic resistance might be influenced by either orthopedic conditions or COVID-19. These manifestations could be relevant and of great interest in the context of this current global health threat; therefore, we summarize the current knowledge and/or the lack of sufficient evidence to support the interactions between these conditions.

Fragility fractures of the pelvis have lately gained interest due to the increased incidence caused by aging populations. The aim of the study was to evaluate the results of the therapy in patients with pelvic fragility fracture admitted between January 2015 and September 2018 St. Spiridon Emergency Hospital in Iasi in order to improve the therapeutic approach. We assessed the correlation between pain and the early mobilization under the weight bearing condition in patients with and without osteoporotic therapy in history. The study emphasizes the role of pain in recovery process and underline the serious consequences of the late detection of bone fragility. Our study had revealed that previous osteoporotic treatment has benefits in the event of a fracture. As a result of this analysis, we consider that the age for the prophylactic measures in bone fragility should go below 60 years.

The aim of this paper was to present the method used for creating a 3D model of a fractured hemipelvis and its accuracy in reproducing dimensions and structural relationships between fractured fragments. A PolyLactic acid model of the hemipelvis was generated with the aid of the 3D printer. Using a 3D model of a complex fracture aids the orthopedic surgeon in planning the intervention and choosing the best fixation method. Patients with pelvic fractures are not usually operated immediately, which is why they can benefit from this technology.

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Preoperative anemia is a common finding among geriatric patients with trochanteric fractures. We assessed the dynamics of hemoglobin and the factors that influence it. A total of 780 patients with trochanteric fractures were selected. Distribution by gender showed a slightly higher proportion of female patients (64.1%). The preoperative interval ranged from a few hours to 19 days. Hospital admission period varied from 1 to 49 days. Hemoglobin ranged from 4.80 to 17.40 g/dl; 43.1% of patients had individual values below the baseline. Individually, the hemoglobin value varied from a decrease of 9.33 g/dL to an increase of 11.97 g/dL, but the total study group recorded an average decrease of 0.96 � 1.75 g/dL. Hemoglobin had a downward trend directly correlated with the preoperative interval period. Decrease in hemoglobin was correlated with the percentage of blood lymphocytes, PLT/WBC ratio, prothrombin activity and APTT ratio. A low level of hemoglobin variation was associated with a shorter preoperative interval, reduced prothrombin time, prothrombin activity ] 100, INR ] 1.50 and APTT ] 30.

Bicondylar tibial plateau fractures pose many challenges in surgical treatment. The aim of the present study was to analyze three methods of reduction, single medial, single lateral, and dual plating, for the treatment of a bicondylar tibial plateau fracture, through finite element analysis (FEA). A simple metaphyseal fracture, type C1.1 (AO-41) was modeled on a CT-derived 3D model of the knee. Lateral and medial proximal tibial polyaxial plates with screws were modeled and placed accordingly for the three methods of reduction. Simulation of physiological type loading corresponding to the maximal weight acceptance phase during a slow walking gait cycle was performed using FEA. Values of stress and strain were recorded near the fracture lines. Dual plating provided a decrease of stress and strain in the tibial plateau area. However, the differences in the values among the three cases were small. The stress concentration areas were located in the vicinity of the fracture, predominantly in the area of the tibial plateau. Considering the limitations of the present study, the results revealed that dual plating leads to smaller stress and strain values near the fracture lines in the tibial plateau area. However, values obtained for single lateral plating are close in range. Considering the complexity of the surgical approach for dual plating, single lateral plating may be a solution for good reduction with fewer surgical risks and complications. Further studies on the C1.1 fracture (AO-41) are needed to analyze the complex issue of reducing and stabilizing such a fracture and to characterize the postoperative state while providing predictable parameters for an optimal result.