Cemented Hemiarthroplasties Are Associated with a Higher Mortality Rate after Femoral Neck Fractures in Elderly Patients.

PURPOSE OF THE STUDY The postoperative outcomes of total hip replacement and hemiarthroplasty after femoral neck fractures in elderly patients were analysed to determine general and local complications as well as morbidity and mortality rates in order to detect risk profiles and assess the best individual treatment option. MATERIALS AND METHODS One hundred sixty-one femoral neck fractures among patients aged ≥ 65 years treated with cemented hemiarthroplasty (HA) or uncemented total hip arthroplasty (THA) between January 2005 and October 2013 were evaluated. In the presence of articular pathologies as well as a fracture type Garden III or IV, the indication for joint replacement was given. Criteria for performing hemiarthroplasty were previously limited mobility. Freely and fully mobilised patients and patients with manifested osteoarthritis received a cementless THA. A comparison of the observed complications was made, differentiating between general and surgery-specific hip-related complications. Furthermore, the mortality rates were analysed in relation to the respective surgical treatment. RESULTS Seventy cemented HA and ninety-one uncemented THA were performed. There was a high complication rate of approximately 19% in both surgical intervention groups. The patients were more likely to develop general complications (HA 12.8%; THA 10.8%) even though cardiopulmonary complications occurred more frequently in the cemented HA group. Four patients died after cemented hemiarthroplasty due to thromboembolic events (5.7% mortality rate), whereas no deaths occurred after total hip replacement. Surgery-specific complications rates were 7.8% in THA and 5.7% in HA patients. CONCLUSIONS THA in eldery patients with femoral neck fractures is associated with a higher complication rate, mostly of general medical entity. After cemented HA, our study reveals a high mortality rate due to thromboembolic events. For patients with multimorbidity in particular, these findings therefore suggest that uncemented THA should be considered to prevent lethal complications. Key words: femoral neck fracture; total hip arthroplasty; hemiarthroplasty; complications.

Adhesion and activation of platelets from subjects with coronary artery disease and apparently healthy individuals on biomaterials.

On the basis of the clinical studies in patients with coronary artery disease (CAD) presenting an increased percentage of activated platelets, we hypothesized that hemocompatibility testing utilizing platelets from healthy individuals may result in an underestimation of the materials' thrombogenicity. Therefore, we investigated the interaction of polymer-based biomaterials with platelets from CAD patients in comparison to platelets from apparently healthy individuals. In vitro static thrombogenicity tests revealed that adherent platelet densities and total platelet covered areas were significantly increased for the low (polydimethylsiloxane, PDMS) and medium (Collagen) thrombogenic surfaces in the CAD group compared to the healthy subjects group. The area per single platelet-indicating the spreading and activation of the platelets-was markedly increased on PDMS treated with PRP from CAD subjects. This could not be observed for collagen or polytetrafluoroethylene (PTFE). For the latter material, platelet adhesion and surface coverage did not differ between the two groups. Irrespective of the substrate, the variability of these parameters was increased for CAD patients compared to healthy subjects. This indicates a higher reactivity of platelets from CAD patients compared to the healthy individuals. Our results revealed, for the first time, that utilizing platelets from apparently healthy donors bears the risk of underestimating the thrombogenicity of polymer-based biomaterials.

Coherent diffractive imaging: towards achieving atomic resolution.

The next generation of X-ray sources will feature highly brilliant X-ray beams that will enable the imaging of local nanoscale structures with unprecedented resolution. A general formalism to predict the achievable spatial resolution in coherent diffractive imaging, based solely on diffracted intensities, is provided. The coherent dose necessary to reach atomic resolution depends significantly on the atomic scale structure, where disordered or amorphous materials require roughly three orders of magnitude lower dose compared with the expected scaling of uniform density materials. Additionally, dose reduction for crystalline materials are predicted at certain resolutions based only on their unit-cell dimensions and structure factors.

[Blood vessel and nerve damage in total hip arthroplasty]. / Gefäß- und Nervenverletzungen in der Hüftendoprothetik.

Blood vessel and nerve damage are uncommon complications in total hip arthroplasty (THA). With an incidence between 0.1 and 0.2 % in primary THA these complications are rare but can be serious with a high mortality risk. The individual risk is determined by multiple factors depending on the surgeon's skills, the number of previous surgeries and the approach itself. The anatomy of the defect is an essential risk factor. Some procedures, such as the use of screws for cup fixation are associated with a higher risk of vascular and neural damage. The acetabular quadrant system of the hip as described by Wasielewski et al. is a useful tool to visualize the neurovascular anatomy of the hip, to detect the safe zone and subsequently prevent complications. Sciatic nerve palsy after total hip replacement is the most common nerve damage followed by femoral nerve damage. Previous surgery, a posterior approach and excessive leg extension are the most common risk factors for nerve damage. In order to diagnose nerve palsy after orthopedic surgery an electromyogram can be of use to assess the extent and prognosis. This article focuses on vascular and neural complications after total hip arthroplasty and the options for diagnosis, treatment and prevention.

Differential ion mobility spectroscopy: non-invasive real-time diagnostics and therapy control in metabolic diseases.

BACKGROUND: Over the last few years, differential ion mobility spectroscopy (DMS) has become an important tool in medical research. There are attempts to find markers for specific diseases in exhaled air, using this technology as a non-invasive early diagnosis. OBJECTIVE: In the present research, exhaled air from 78 patients with known diagnosis and 39 control persons were tested with a DMS system from Sionex. RESULTS: Bronchial asthma showed a pattern of 6 characteristic points in a discriminant analysis. Patients with diagnosed hypertension showed a characteristic pattern with 4 points, hypothyroidism 2 points; increased LDL cholesterol 3 points, and type II diabetics treated with insulin 4 spots. No significant differences with respect to the control group were found in chronic obstructive pulmonary disease patients. The DMS pattern in the tested asthmatics showed a partial change depending on different medications used. CONCLUSION: Differential ion mobility spectroscopy offers promise as a helpful diagnostic tool.

Ritually induced growth disturbances and deformities of the orofacial system--a contribution to cranial morphogenesis.

Numerous ritual acts involving the skull result in orofacial changes. The present study focuses on ritual acts of Brazilian Zoé Indians. A distinct deformation effect of the ritual act (wearing a lip-plug) on the morphology of the orofacial system is demonstrated and documented using jaw models. The studies show that the lip-plug significantly influences tooth position and jaw growth. While the maxilla displays palatal displacement of the lateral incisors and elevation of the palate, retraction occurs in the mandible depending upon plug size. Additionally, both the plug and the nutritional habits of the Indians induce marked abrasion of all teeth. Moreover, it is shown that the duration of lip-plug wear is an essential determinant of sustained orofacial changes.

The ultrastructure and processing properties of Straumann Bone Ceramic and NanoBone.

The ultrastructure, fundamental chemistry, and processing modes of fully synthetic bone grafting materials are relevant to the reconstruction of osseous defects. Rapid progress in the profitable market of biomaterials has led to the development of various bone substitutes. Despite all these efforts, an ideal and full substitute of autologous bone is not yet in sight. With regard to anorganic calcium phosphate ceramics, Straumann Bone Ceramic and NanoBone are compared. These have a similar composition and are osteoconductive, which indispensably requires contact with well-vascularised bone.

Histological and fluorescence microscopic examination of the bone/implant interface in orthodontic miniscrews (Mondeal).

The temporary nature of orthodontic implants demands optimisation of size and design in order to minimise damage and risk to the patient. Slender and shorter miniscrews offer the advantage over conventional implants of easier and more ubiquitous positioning with minimised risk of injury to neighbouring anatomical structures such as tooth roots, nerves or vessels. The question is raised, however, as to what extent these advantages are gained at the price of diminished stability or a more unfavourable bone interface. In order to evaluate the screw/bone interface, 14 orthodontic miniscrews (Mondeal Medical Systems, diameter: 1.5 mm, length: 9 mm) were inserted into the right and left mandibles of 7 pigs (Sus scrofa domestica). Bone fluorochromes were administered in a defined order for polychrome sequencing. The samples gathered after 70 days were analysed using histological techniques and fluorescence microscopy. The lower part of the self-tapping thread displayed undisturbed bone apposition. Fluorescence microscopy revealed remodelling and bone apposition within the thread grooves.

The use of ceramic drills on a zirconium oxide basis in bone preparation.

The favourable mechanical properties and high biocompatibility of the newly developed mixed ceramics composed of zirconium oxide and aluminium oxide have continuously extended the scope of their application. Rotating instruments on a zirconium oxide basis are regarded as superior to metal burs in dentoalveolar surgery in terms of favourable temperature effects on the surrounding bone tissue and the economic advantage that they wear slowly, enabling them to be used repeatedly. In this study ten round burs made of zirconium oxide and aluminium oxide mixed ceramics were used for typical dental-alveolar preparation types on an explanted pig jaw. Prior to the first and following the tenth application a scanning electron microscopic (SEM) analysis of possible wear signs was conducted. However, this revealed no evidence of wear or resulting loss of sharpness.

Bacterial colonisation of interior implant threads with and without sealing.

Premature loss of dental implants is due, apart from mechanical factors, to germrelated inflammation. Gaps and hollow spaces within the implant system, for example the gap between implant and abutment in the two-part implant system, may provide a bacterial reservoir causing or maintaining inflammation. The bacterial spectrum involved is similar to that found in periodontitis. This in vitro study aimed to scrutinise the capability of Porphyromonas gingivalis (DSM 20709), the bacterium blamed for inducing peri-implantitis, to pass the implant/abutment gap in titanium implant systems used for orthodontic anchorage and to remain vital in the interior. Additionally, the in vitro effectiveness of gutta percha for gap sealing was examined. Twelve titanium implants (Straumann, diameter: 3.3 mm, length 5.5 mm) were provided with abutments at a defined torque (20 Ncm), six of which were sealed with gutta percha before screwing in the abutment. Subsequently the implants were placed in a nutrient solution (thioglycolate boullion with haemin-menadione solution) that contained Porphyromonas gingivalis. Microbiological specimens were sampled from the implant interiors after 24 and 72 hours and analysed using culture methods. There was evidence that penetration of the periodontal pathogen Porphyromonas gingivalis to the implant interior may occur as early as after 24 hours. Microbes were also detected in the interior of implants sealed with gutta percha. The abutment/implant interface in vitro provides a microbiological leakage for the prospective peri-implantitis-inducing bacterium Porphyromonas gingivalis. Survival of the bacterium is possible in the interior, so that development of a bacterial reservoir is assumed. This in vitro trial produced no evidence that sealing with gutta percha is an effective means to prevent secondary bacterial colonisation in the implant interior.

The survival and proliferation of fibroblasts on orthodontic miniscrews with different surface treatment: an in vitro study.

It is of fundamental importance for prosthodontic and orthodontic applications that there is a short osseointegration time of dental implants without inflammation of the surrounding tissue. In addition to the chemical properties of the implant material, the surface morphology is an equally critical parameter. The objective of this work was to study the effect of two simple surface treatments on the survival and proliferation of fibroblasts. Three groups of orthodontic miniscrews (Mondeal) were used. One group was given an airflow (EMS, Schweiz) treatment, the second was sand-blasted in the area of the threading and a third group served as a control. After preparation sterilised screws were cultured in vitro with fibroblasts (L-929). The metabolic cell activity on the implant surface was determined after 24, 48 and 120 hours using the alamarBlue assay and a count of DAPI labelled fibroblasts was performed with a fluorescence microscope. After 24 hours, but not at 48 hours and 120 hours, the metabolic activity of the fibroblasts was slightly decreased for the airflow screw group. Generally, no significant difference was found regarding metabolic activity and proliferation of fibroblasts within the different groups.

Requirements and infection prophylaxis for internally cooled implant drills.

Implant site preparation is crucially important to long-term success. Heat generation during drilling is unfavourable, since bone is relatively susceptible to heat, depending on its vascularisation and microstructure. Numerous factors such as drilling pressure, number of revolutions, drill design, wear and material, drilling depth and cooling influence heat generation. Internally cooled drills are, therefore, increasingly used, even though the improved cooling effect compared to conventional externally cooled drills is controversial. Internally cooled drills may have the disadvantage of a germ reservoir developing in the cooling channel. This study aimed to examine the effects of disinfection and sterilisation of internally cooled drills. After contamination of the cooling channel with suitable bioindicators (Enterococcus faecium, ATCC 6057 and spores of Bacillus stearothermophilus, ATCC 7953), the drills were disinfected (disinfection solution ID 220, Dürr Dental) and autoclaved (Webeco, E5S90, 134 degrees C, 2.6 bar, 5 min). Disinfection was not completely effective except after pre-cleaning. By means of sterilisation all spores of Bacillus stearothermophilus were completely killed. Internally cooled drills can be successfully disinfected by means of this hygienic procedure routinely used in dental practice and no source of infection is created.

The morphological and clinical relevance of mandibular and maxillary bone structures for implantation.

Tooth loss, which interrupts the biocybernetic feedback circuit of the masticatory system, changes the structures of the jaw bone: such changes are termed "inactivity atrophy". The mandible is subject to vertical atrophy and the maxilla is primarily subject to horizontal atrophy. The mandible possesses more compact bone, the maxilla more spongy; the resorption directions also differ (mandible: towards the oral aspect; maxilla: towards the vestibular). An implant helps to restore the biocybernetic feedback system. The amount of available bone, bone structure, and topographic conditions are crucial factors influencing implant success. Osseointegration is performed at an early stage (which includes bleeding, granulation tissue, foreign-body recognition, interactions) and at a late stage (so-called osseous bridging, development of fibrous and lamellar bone).

Effect of conditioning with d-amphetamine on the extracellular concentration of dopamine and its metabolites in the striatum of behaving rats.

The effect of classical conditioning with d-amphetamine on the extracellular concentrations of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the striatum of awake, freely moving rats was studied using microdialysis. This was done in order to test, whether there occurred alterations in DA release as conditioned responses in the striatum. The first series of experiments studied the acute effects of d-amphetamine on the concentration of DA and its metabolites DOPAC and HVA. d-Amphetamine (2 mg/kg, s.c.) increased extracellular DA and decreased DOPAC and HVA. Behaviorally, it led to stereotyped locomotor activation and sniffing. In principle, these observations confirmed earlier findings. In a second series, conditioned responses to d-amphetamine were studied. Rats were implanted with guide cannulas prior conditioning experiments started. For conditioning experiments, the rats were divided into three groups: conditioned group, pseudoconditioned group and a drug-naive control group. After 7 daily training sessions with d-amphetamine (2 mg/kg), on the 8th day, the test day, rats were injected with saline and exposed to the conditional stimuli, while they were observed for their stereotyped, conditioned response. Additionally, microdialysis was performed in order to observe possible changes in the extracellular transmitter or metabolite concentrations. Conditioning with amphetamine led to conditioned stereotypic behavior. In comparison with the pseudoconditioned rats, there was an increase in DA release as conditioned response to amphetamine. In pseudoconditioned rats. DOPAC and HVA were slightly higher than in both other groups. DOPAC and HVA were lower in rats conditioned to d-amphetamine when compared with the pseudoconditioned ones.(ABSTRACT TRUNCATED AT 250 WORDS)

Recordings of extracellular glutamate and gamma-aminobutyric acid in the striatum of non-anesthetized rats. K(+)-stimulation, its Ca(2+)-dependence and lack of effects of drugs acting on dopamine receptors.

The extracellular concentrations of glutamate (GLU) or gamma-aminobutyric acid (GABA) in the striatum were determined in non-anesthetized, non-restrained rats using the microdialysis method, and the effects of some dopaminergic drugs were studied. Since a great part of these amino acids in the extracellular space is probably of origin not related to neurotransmission, the percentage of amino acids of neuronal origin was increased by stimulation with K+ added to the perfusion medium, and the Ca(2+)-dependence of K+ stimulated release was checked. This stimulation was performed twice in most of the experiments, under standard condition and after specific manipulations. K+ (100 mmol/l) produced pronounced increases in the overflow of GLU and even more of GABA. Omission of Ca2+ and addition of 20 mmol/l of Mg2+ in the medium significantly decreased the K(+)-stimulated overflow of GLU, but not of GABA. However, when in the whole perfusion procedure K+ was elevated and, initially, the medium was kept Ca(2+)-free, but contained 20 mmol/l of Mg2+, and subsequently was replaced by a medium containing Ca2+, but no Mg2+, then the shift to the second medium led to considerable increases in overflow both of GLU and GABA indicating a partial Ca(2+)-dependence of K(+)-stimulated overflow and suggesting at least a partial neuronal origin of the extracellular amino acids. In subsequent experiments, dopaminergic drugs were administered systemically before the second stimulation with K+. Apomorphine (2 mg/kg s.c.) had no effect on the K(+)-stimulated GABA overflow.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of extracellular glutamate after local K+ stimulation in the striatum of non-anaesthetised rats after treatment with dopaminergic drugs--studies using microdialysis.

The present experiments were performed in order to investigate the effects of dopamine(DA)ergic drugs on the concentrations of extracellular glutamate (GLU) in the striatum of non-anaesthetised, freely moving rats by using microdialysis and to get further information about the interactions between glutamatergic and dopaminergic pathways. GLU was determined after pre-column derivatisation with o-phthaldialdehyde by HPLC and fluorescence detection. For increasing the fraction of extracellular GLU which is of neuronal origin, an enhanced release of this neurotransmitter was evoked by 100 mM K+ administered via the dialysis probe. This stimulation was applied twice in each experiment, at the second time after administration of a subcutaneously (s.c.) given DAergic drug. For basal conditions, a perfusion fluid containing 148.2 mM Na+, 4mM K+, 1.2 mM Ca2+ was used, for conditions of stimulation with 100 mM K+ the Na+ concentration was reduced correspondingly. Activation of the D1 receptor with the selective D1 sector agonist SKF 38393 ((+/-) 1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine-7,8-diol) 15 mg/kg) failed to influence the stimulated release of GLU, and neither a combination of the selective D2 antagonist (-)sulpiride (150 mg/kg) with the mixed D1/D2 agonist apomorphine (1 mg/kg), nor a combination of sulpiride (150 mg/kg) with SKF 38393 (15 mg/kg) were effective. Also the two selective D2 agonists quinpirole (0.5 mg/kg) or talipexole (50 micrograms/kg) had no significant influence on the release of GLU. The results suggest that DA receptor agonists have less effect on the K(+)-stimulated GLU-release than might be expected from in vitro studies or behavioral experiments (Kornhuber and Kornhuber, 1986).

A new, highly sensitive enzymic assay for human tryptase and its use for identification of tryptase inhibitors.

A chromogenic two-stage assay for human tryptase, a specific marker of mast cell activation, was developed based on the tryptase-induced conversion of prothrombin to thrombin. This assay proved to be more sensitive and reliable than measurements of amidolytic activity of tryptase with small synthetic substrates such as Bz-Arg-Nan and was suitable to detect tryptase activity in human body fluids. In addition, the assay was useful for studies of natural and recombinant inhibitors of tryptase.