Smoking is a predictor of worse trabecular mechanical performance in hip fragility fracture patients.

Clinical risk factors (CRFs) are established predictors of fracture events. However, the influence of individual CRFs on trabecular mechanical fragility is still a subject of debate. In this study, we aimed to assess differences, adjusted for CRFs, between bone macrostructural parameters measured in ex-vivo specimens from hip fragility fracture patients and osteoarthritis patients, and to determine whether individual CRFs could predict trabecular bone mechanical behavior in hip fragility fractures. Additionally, we also looked for associations between the 10-year risk of major and hip fracture calculated by FRAX and trabecular bone mechanical performance. In this case-control study, a group of fragility fracture patients were compared with a group of osteoarthritis patients, both having undergone hip replacement surgery. A clinical protocol was applied in order to collect CRFs [body mass index (BMI), prior fragility fracture, parental history of hip fracture, long-term use of oral glucocorticoids, rheumatoid arthritis, current smoking, alcohol consumption, age and gender]. The 10-year probability of fracture was calculated. Serum bone turnover markers were determined and dual X-ray absorptiometry performed. Femoral head diameter was evaluated and trabecular bone cylinders were drilled for mechanical testing to determine bone strength, stiffness and toughness. We evaluated 40 hip fragility fracture and 52 osteoarthritis patients. Trabecular bone stiffness was significantly lower (p = 0.042) in hip fragility fracture patients when compared to osteoarthritic individuals, adjusted for age, gender and BMI. No other macrostructural parameter was statistically different between the groups. In hip fragility fracture patients, smoking habits (ß = -0.403; p = 0.018) and female gender (ß = -0.416; p = 0.008) were independently associated with lower stiffness. In addition, smoking was also independently associated with worse trabecular strength (ß = -0.323; p = 0.045), and toughness (ß = -0.403; p = 0.018). In these patients, the 10-year risk of major (r = -0.550; p = 0.012) and hip fracture (r = -0.513; p = 0.021) calculated using only CRFs was strongly correlated with femoral neck bone mineral density but not with mechanical performance. Our data showed that among fragility fracture patients active smoking is a predictor of worse intrinsic trabecular mechanical performance, and female gender is also independently associated with lower stiffness. In this population, the 10-year risk of fracture using CRFs with different weights only reflects bone mass loss but not trabecular mechanical properties.

Biodegradable Iron and Porous Iron: Mechanical Properties, Degradation Behaviour, Manufacturing Routes and Biomedical Applications.

Biodegradable metals have been extensively studied due to their potential use as temporary biomedical devices, on non-load bearing applications. These types of implants are requested to function for the healing period, and should degrade after the tissue heals. A balance between mechanical properties requested at the initial stage of implantation and the degradation rate is required. The use of temporary biodegradable implants avoids a second surgery for the removal of the device, which brings high benefits to the patients and avoids high societal costs. Among the biodegradable metals, iron as a biodegradable metal has increased attention over the last few years, especially with the incorporation of additive manufacturing processes to obtain tailored geometries of porous structures, which give rise to higher corrosion rates. Withal by mimic natural bone hierarchical porosity, the mechanical properties of obtained structures tend to equalize that of human bone. This review article presents some of the most important works in the field of iron and porous iron. Fabrication techniques for porous iron are tackled, including conventional and new methods highlighting the unparalleled opportunities given by additive manufacturing. A comparison among the several methods is taken. The effects of the design and the alloying elements on the mechanical properties are also revised. Iron alloys with antibacterial properties are analyzed, as well as the biodegradation behavior and biocompatibility of iron. Although is necessary for further in vivo research, iron is presenting satisfactory results for upcoming biomedical applications, as orthopaedic temporary scaffolds and coronary stents.

Biodegradable Bone Implants as a New Hope to Reduce Device-Associated Infections-A Systematic Review.

Bone fractures often require fixation devices that frequently need to be surgically removed. These temporary implants and procedures leave the patient more prone to developing medical device-associated infections, and osteomyelitis associated with trauma is a challenging complication for orthopedists. In recent years, biodegradable materials have gained great importance as temporary medical implant devices, avoiding removal surgery. The purpose of this systematic review was to revise the literature regarding the use of biodegradable bone implants in fracture healing and its impact on the reduction of implant-associated infections. The systematic review followed the PRISMA guidelines and was conducted by searching published studies regarding the in vivo use of biodegradable bone fixation implants and its antibacterial activity. From a total of 667 references, 23 studies were included based on inclusion and exclusion criteria. Biodegradable orthopedic implants of Mg-Cu, Mg-Zn, and Zn-Ag have shown antibacterial activity, especially in reducing infection burden by MRSA strains in vivo osteomyelitis models. Their ability to prevent and tackle implant-associated infections and to gradually degrade inside the body reduces the need for a second surgery for implant removal, with expectable gains regarding patients' comfort. Further in vivo studies are mandatory to evaluate the efficiency of these antibacterial biodegradable materials.

Surface and mechanical properties of a nanostructured citrate hydroxyapatite coating on pure titanium.

The presence of a biomimetic HAP coating on titanium surface, which reduces the structural stiffness, is essential to improve implants biocompatibility and osteointegration. In this study, new citrate-HAP (cHAP) coatings were produced by a simple hydrothermal method on pure titanium (Ti) surface, without requiring any additional pretreatment on this metal surface. The formed cHAP coatings consisting of nanorod-like hydroxyapatite particles, conferred nanoroughness and wettability able to endow improved biological responses. Indeed, the presence of citrate species in the precipitate medium seems to be responsible for controlling the morphology of the new coatings. The presence of citrate groups on the surface of cHAP coatings, identified by chemical composition analysis, due to their implication in bone metabolism can additionally bring an add-value for bone implant applications. From a mechanical point of view, the Finite Element algorithm showing that cHAP coatings tend to decrease the mechanical stress at pure Ti, further favors these new coatings applicability. Overall, the simple and expedite strategy used to developed new biomimetic coatings of citrate-HAP resulted in improved physicochemical, morphological and mechanical properties of Ti, which can endeavor improved implantable materials in bone healing surgical procedures.

The Contribution of a Whey Protein Film Incorporated with Green Tea Extract to Minimize the Lipid Oxidation of Salmon (Salmo salar L.).

Active packaging is becoming progressively more significant as a response to the dynamic changes in current consumer demand and market tendencies. Active packaging is projected to interact directly with the packaged food or with the headspace within the package with the aim of maintaining or extending product quality and shelf-life. Aiming for sustainability, the potential application as biodegradable films of whey protein concentrate (WPC) was evaluated. Aromatic plant's extracts present high antioxidant properties, representing an alternative for synthetic food additives. The main objective of this study was to verify the effectiveness of an edible WPC film incorporated with a plant-based extract on retarding the lipid oxidation of fresh salmon. Green tea extract (GTE) was chosen to be incorporated into the active film. Fresh salmon was packaged with the control film (WPC) and with active film (WPC-GTE). The oxidation level of non-packaged samples and packaged samples were tested for different storage times. Four methods were applied to evaluate lipid oxidation state of fresh salmon: peroxide value, p-anisidine value, thiobarbituric acid reactive substances (TBARS) assay, and monitoring of hexanal. The results obtained in this study indicate that the whey protein active film was successfully produced, and it was effective in delaying lipid oxidation of fresh salmon samples until the 14th day of storage.

Chronic Hyperglycemia Modulates Rat Osteoporotic Cortical Bone Microarchitecture into Less Fragile Structures.

There is controversy concerning the diabetes impact on bone quality, notorious in type 2 diabetic postmenopausal women. One pointed cause might be uncontrolled glycemia. In this study, the effect of chronic hyperglycemia in bone turnover, morphology, and biomechanics was evaluated in female Wistar rats in the presence/absence of estrogens (ovariectomy). Animals (n = 28) were divided into sham, ovariectomized (OVX), hyperglycemic (streptozotocin 40 mg/kg, single-dose i.p.-STZ), and hyperglycemic-ovariectomized (STZ + OVX) animals. Blood biomarkers were estimated 60 days postovariectomy. Body weight, vertebral microarchitecture (L4-histomorphometry), femur biomechanical properties (bending tests), tibia ultrastructure (scanning electron microscopy), and femur and urinary calcium (atomic absorption) were also evaluated. The increased PINP/CTX ratio of hyperglycemic animals and the similar ratio between STZ + OVX and healthy animals contrasting with the lower ratio of OVX (in line with its histomorphometric data) suggest a tendency for improved bone formation in hyperglycemic-ovariectomized animals. The increased tibia medullar canal, which contrasts with the unaffected cortical thickness of both hyperglycemic groups while that of OVX decreased, was associated to the increased stiffness and strength of STZ + OVX bones compared to those of OVX, in line with the observed ultrastructure. Concluding, chronic hyperglycemia in ovariectomized female rats causes bone morphological changes that translate positively in the ultrastructure and mechanical properties of cortical bones.

Arthritis induces early bone high turnover, structural degradation and mechanical weakness.

BACKGROUND: We have previously found in the chronic SKG mouse model of arthritis that long standing (5 and 8 months) inflammation directly leads to high collagen bone turnover, disorganization of the collagen network, disturbed bone microstructure and degradation of bone biomechanical properties. The main goal of the present work was to study the effects of the first days of the inflammatory process on the microarchitecture and mechanical properties of bone. METHODS: Twenty eight Wistar adjuvant-induced arthritis (AIA) rats were monitored during 22 days after disease induction for the inflammatory score, ankle perimeter and body weight. Healthy non-arthritic rats were used as controls for compar-ison. After 22 days of disease progression rats were sacrificed and bone samples were collected for histomorphometrical, energy dispersive X-ray spectroscopical analysis and 3-point bending. Blood samples were also collected for bone turnover markers. RESULTS: AIA rats had an increased bone turnover (as inferred from increased P1NP and CTX1, p = 0.0010 and p = 0.0002, respectively) and this was paralleled by a decreased mineral content (calcium p = 0.0046 and phos-phorus p = 0.0046). Histomorphometry showed a lower trabecular thickness (p = 0.0002) and bone volume (p = 0.0003) and higher trabecular sepa-ration (p = 0.0009) in the arthritic group as compared with controls. In addition, bone mechanical tests showed evidence of fragility as depicted by diminished values of yield stress and ultimate fracture point (p = 0.0061 and p = 0.0279, re-spectively) in the arthritic group. CONCLUSIONS: We have shown in an AIA rat model that arthritis induc-es early bone high turnover, structural degradation, mineral loss and mechanical weak-ness.