BACKGROUND: The acromion projects laterally in a curving orientation. When a fracture of the acromion occurs, despite being rare, matching the best-fit fixation plate is challenging due to few options and limited availability of fixation plate types. Alternative fixation methods can carry risk of nonunion complications. PURPOSE: The objective of this study was to investigate the morphological curvature pattern of the acromion to assess the level of the fixation plates fitness and provide the suitable imaging modalities for evaluating the acromion curvature. BASIC PROCEDURES: The correlation between the acromion curvature and five fixation plates were calculated and their fitness level was evaluated statistically. The curvature of acromion and the five available fixation plates were photographed and assessed digitally by software (FIJI ImageJ and Microsoft Excel). The method entails plotting seven points along the curving surface and margins of the acromion, while the Excel Solver function calculates the regression, ultimately giving curvature values. First, the acromion parameters were studied on 180 paired healthy dry scapulae. Then, the acromion curvature values were compared to the fixation plates curvatures. Likewise, the acromion curvature was assessed as applicable on 153 (100 AP- views, 50 Y- views, and 3 superior-views) retrospective plain X-rays and 40 3D-CT scapula reconstructions of healthy acromia. MAIN FINDINGS: The mean length of the acromion was 48.70 ± 5.29 mm, mean thickness was 8.51 ± 1.67 mm, and mean width was 25.97 ± 5.97 mm. The calculated values of the mean curvatures were 0.050 ± 0.015 mm-1 for the mean acromion surface, 0.042 ± 0.027 mm-1 for the internal margin, and 0.055 ± 0.010 mm-1 for the external margin. The curved geometry of the acromion was plotted on a graph giving a spectrum of curvature patterns with distribution values revealing fixation plates fitness represented by area under the curve with frequencies of 4.32 % for the acromion-specific fixation plate, 14.28 % for the large clavicle fixation plate, 0.26 % for the small clavicle fixation plate, 53.38 % for the flexible universal fixation plate, and none for the rigid universal fixation plate. PRINCIPAL CONCLUSIONS: Approximately 27.76 % of the acromion surface curvatures distribution does not overlap with any of our measured fixation plates. Evaluating the acromion surface curvature was possible on plain X-rays in the Y-view only.
- Keywords
- Acromion, Acromion curvature, Acromion fixation, Acromion fractures,
- MeSH
- Acromion * diagnostic imaging injuries anatomy & histology surgery MeSH
- Fractures, Bone * surgery diagnostic imaging MeSH
- Bone Plates * MeSH
- Humans MeSH
- Scapula * diagnostic imaging anatomy & histology MeSH
- Radiography MeSH
- Fracture Fixation, Internal * methods instrumentation MeSH
- Check Tag
- Humans MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
This study investigated the mechanical, thermal, and morphological properties of acrylonitrile butadiene styrene (ABS)-based nanocomposites reinforced with different types and concentrations of nanofillers. The uniaxial tensile testing results indicated that Young's modulus (E) generally decreased with increasing filler content, except at 0.500 w.% filler concentration, where a slight increase in stiffness was observed. A statistically significant interaction between sample type and filler concentration was identified (p = 0.045). Fracture toughness measurements revealed a significant reduction in impact resistance at 1.000 w.% filler concentration, with values dropping by up to 67% compared with neat acrylonitrile butadiene styrene. Dynamic mechanical vibration testing confirmed a decrease in stiffness, as evidenced by a shift of the first resonance frequency (fR1) to lower values. Hardness measurements including indentation and Shore D hardness exhibited an increasing trend with rising filler concentration, with statistically significant differences observed at specific concentration levels (p < 0.05). Scanning electron microscopy analysis showed that nanofillers were well dispersed at lower concentrations, but agglomeration began above 0.500 w.%, resulting in void formation and a noticeable decline in mechanical properties. The results suggest that an optimal filler concentration range of 0.250-0.500 w.% offers an ideal balance between enhanced mechanical properties and material integrity.
- Keywords
- ABS polymer, calcium carbonate, halloysite, mechanical testing, nanocellulose,
- Publication type
- Journal Article MeSH
Surfaces of cubic perovskite oxides attract significant attention for their physical tunability and high potential for technical applications. Bulk-terminated surfaces are desirable for theoretical modeling and experimental reproducibility, yet there is a lack of methods for preparing such well-defined surfaces. We discuss a method for strain-assisted cleaving of perovskite single crystals, using a setup easily transferable between different experimental systems. The details of the cleaving device and the procedure were optimized in a systematic study on the model cubic perovskite oxide SrTiO3. The large-area morphology and typical distribution of surface terminations on cleaved SrTiO3(001) are presented, with specific guidelines on how to distinguish well-cleaved surfaces from conchoidally fractured ones. The cleaving is applicable to other cubic perovskites, as demonstrated on KTaO3(001) and BaTiO3(001). This approach opens up a pathway for obtaining high-quality surfaces of this promising class of materials.
- Publication type
- Journal Article MeSH
The objective of the present work was to prepare hybrid epoxy composites with improved mechanical and thermal properties. The simultaneous use of two different modifiers in an epoxy resin was motivated by the expected occurrence of synergistic effects on the performance properties of the matrix. Such a hybrid composite can be used in more severe conditions and/or in broader application areas. Hybrid epoxy composites were prepared with polyurethane (PUR), Nanomer nanoclay and carbon nanotubes (CNT), followed by the evaluation of their mechanical and thermal properties. Synergistic improvements in mechanical properties of hybrid composites were observed for 0.5 wt% Nanomer and 1 wt% carbon nanotubes (CNT), 7.5 wt% PUR and 1 wt% CNT, and 5 wt% PUR and 1 wt% CNT, confirming the occurrence of synergistic effects as to the impact strength (IS) of the matrices, compared to binary systems. The toughening induced by CNT/Nanomer modifiers can be attributed to the specific interfacial interactions between the two nanoparticles, while in the case of CNT/PUR, it can be explained by the combined effects of flexible polymer chains and the specific arrangement of nanoparticles in epoxy systems. Spectroscopy analysis confirmed the occurrence of interaction between OH groups in the epoxy matrix with CNT and reactive groups of PUR. The fracture surface showed plastic deformations, with good dispersion of CNT, explaining the improved mechanical properties of the matrix composites.
- Keywords
- epoxy hybrids, mechanical properties, structure and morphology, synergism, thermal properties,
- Publication type
- Journal Article MeSH
The present study investigated the effects of thermal aging, ultraviolet radiation (UV), and stress softening on the performance properties of rubber modified with Cloisite Na+ or Cloisite 20A. Tensile strength (TS), strain at break (SB), modulus, and the retention coefficient were measured before and after aging. Results showed that TS and SB decreased by about 50% after 7 days of aging for all tested samples due to the breakage of the chemical bonds between rubber and nanoparticles. The modulus at 300% elongation increased by 20%, 15%, and 7% after thermal aging for the unmodified sample, nanocomposites with Cloisite Na+, and Cloisite 20A, respectively. The shape retention coefficient of all samples was not affected by heat, except for the virgin rubber sample, which exhibited a decrease of about 15% under thermal aging. The virgin matrix and nanocomposites showed different values of aging coefficient during thermal aging and UV radiation. The dissipated energy of samples that were aged after stretching was slightly higher than that of samples that were aged after stretching due to the breakdown of the bonds within the nanocomposites. Loading-reloading energy results showed that the level of stress softening was lower when Mullins was applied after the aging of the samples. Differential scanning calorimetry results indicated a slight decrease in Tg1 in the aged and stretched samples and an increase in the temperature of the first endothermic peak due to the addition of nanofillers in the stretched and aged samples. Thermogravimetric analysis revealed that all tested samples exhibited similar thermograms, regardless of their state of stretching or aging. Scanning electron microscopy analysis showed that the fracture surface of the virgin unaged sample was rough with some holes, while it was flatter and less rough after aging.
- Keywords
- Mullins effect, aging, mechanical properties, morphology, rubber nanocomposites, structure, thermal properties,
- Publication type
- Journal Article MeSH
PURPOSE OF THE STUDY: To investigate the effects of anatomical variations on the mechanism of scaphoid fracture by comparing the radiologic parameters of the wrist of patients with and without scaphoid fracture after a fall on an outstretched hand. MATERIAL AND METHODS: Cross-sectional comparative retrospective analysis of radiographs of patients with (Group 1, n=169) and without scaphoid fracture (Group 2, n=188). Morphometric data were measured including radial inclination (RI), radial height (RH), ulnar variance (UV), carpal height (CH) ratio, revised carpal height (RCH) ratio and palmar tilt of the distal radius (PT). Receiver operating characteristics (ROC) curve analysis was used to assess the diagnostic performance for each variable with statistically significant difference. RESULTS: The mean RI and PT degrees and RH length were statistically significantly higher, and the mean UV was lower in Group 1 compared to Group 2. No difference was determined between the groups with respect to the CH ratio and RCH ratio. With ROC curve analysis, the cut-off value with the highest odds ratio was determined as RH (Cut-off value=10.77 mm, OR=21.886). CONCLUSIONS: Although higher RI, RH, PT values and more negative ulnar variance were observed in the scaphoid fracture group compared to the non-fracture group, ROC curve analysis showed that only increased RH can be considered as a possible risk factor for scaphoid fractures after fall on an outstretched hand. KEY WORDS: radiographs, risk factor, scaphoid fracture, wrist morphology.
- MeSH
- Scaphoid Bone * injuries diagnostic imaging MeSH
- Adult MeSH
- Fractures, Bone * diagnostic imaging etiology MeSH
- Middle Aged MeSH
- Humans MeSH
- Adolescent MeSH
- Young Adult MeSH
- Wrist Injuries diagnostic imaging etiology MeSH
- Cross-Sectional Studies MeSH
- Radiography * methods MeSH
- Retrospective Studies MeSH
- Accidental Falls * MeSH
- Wrist Joint diagnostic imaging MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Adolescent MeSH
- Young Adult MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Comparative Study MeSH
Bosworth fracture (BF) is a special type of locked ankle fracture-dislocation, characterized by displacement of a fragment of the fractured fibula from the fibular notch behind the posterior surface of the distal tibia. BF is a complex injury affecting multiple structures of the ankle joint, which is still frequently misjudged even today, potentially leading to severe complications. CT examination, including 3D reconstructions, should be the diagnostic standard in BF, as it provides a complete picture of the fracture pathoanatomy, most prominently the morphology of the frequently associated posterior malleolar fracture. BF requires early reduction of the displaced fibular fragment without repeated attempts on closed reduction. Non-operative treatment of BF almost always fails. The standard treatment procedure is early open reduction internal fixation. Due to the relative severity and paucity of the injury, BF seems to be particularly prone to soft tissue complications, including compartment syndrome. The results of operative treatment are mixed. Many studies report persistent pain even after a short time interval, with limitations of the range of motion or even stiffness of the ankle joint, and development of degenerative changes. Larger studies with long-term results are still missing.
- Keywords
- Ankle fracture, Bosworth fracture, compartment syndrome, posterior malleolus fracture,
- Publication type
- Journal Article MeSH
- Review MeSH
INTRODUCTION: 3D printing, a concept over 40 years old, is finding broader application in clinical practice thanks to technological advancements. At University Hospital Ostrava, 3D printing is utilized to create anatomically accurate models of specific patients before surgical procedures based on imaging data. CASE SERIES: 3D printing is employed as a complement to conventional imaging methods to produce morphologically precise models of anatomical structures of individual patients. These models primarily serve for preoperative planning in elective abdominal, vascular, and thoracic surgery. They are also used in planning osteosynthesis of complex fractures and corrective osteotomies. Multicolor printing, although increasing the process's time demands, allows better clarity and differentiation of individual anatomical structures within a single model. DISCUSSION: Compared to 2D images, 3D models provide better spatial orientation and awareness of the operated structures, contributing to improved surgical outcomes. The benefits of 3D printing in preoperative planning and patient education are confirmed by studies across the fields ranging from cardiac surgery to traumatology. CONCLUSION: After overcoming initial challenges, 3D printing has become a reliable component of the surgical arsenal at University Hospital Ostrava for elective surgery. While 3D printing does not represent a universal answer to all medical challenges, its role is highly beneficial and promising in many indicated cases.
- Keywords
- 3D printing, imaging technologies, personalized medicine, precision medicine, preoperative planning, surgical navigation,
- MeSH
- Printing, Three-Dimensional * MeSH
- Models, Anatomic * MeSH
- Surgical Procedures, Operative * MeSH
- Humans MeSH
- Patient Care Planning * MeSH
- Preoperative Period * MeSH
- Check Tag
- Humans MeSH
- Publication type
- English Abstract MeSH
- Journal Article MeSH
- Comparative Study MeSH
STATEMENT OF PROBLEM: Fatigue failure of implant components is a common clinical problem. Plasma nitriding, an in situ surface-strengthening method, may improve fatigue properties of dental implants. PURPOSE: The purpose of this in vitro study was to evaluate the effect of plasma nitriding on the fatigue behavior of implant systems. MATERIAL AND METHODS: The preload and friction coefficient of plasma nitrided abutment screws, as well as settlement of the implant-abutment interface, were measured. Then, the reverse torque values and pullout force were evaluated after cyclic loading. Finally, the fatigue properties of the implant system were investigated with static fracture and dynamic fatigue life tests, and the morphology of the fracture on the surface of the implant system was observed. RESULTS: The plasma nitriding treatment reduced the friction coefficient; increased the preload, settlement value, reverse torque values, pullout force, and static fracture load; and prolonged fatigue life. Furthermore, abutment screws with plasma nitriding treatment showed a different fatigue fracture mode. CONCLUSIONS: Plasma nitriding improved mechanical performance and may be a suitable way to optimize the fatigue behavior of dental implants.
- MeSH
- Dental Stress Analysis methods MeSH
- Dental Implant-Abutment Design MeSH
- Dental Abutments MeSH
- Materials Testing MeSH
- Torque MeSH
- Friction MeSH
- Dental Implants * MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Dental Implants * MeSH
PURPOSE OF THE STUDY The study aimed to draw up a diagnosis and treatment guidelines for the management of the most common compression fractures of the thoracolumbar spine in children. MATERIAL AND METHODS Between 2015 and 2017, pediatric patients with a thoracolumbar injury aged 0-12 years were followed up in the University Hospital in Motol and the Thomayer University Hospital. The age and gender of the patient, injury etiology, fracture morphology, number of injured vertebrae, functional outcome (VAS and ODI modified for children), and complications were assessed. An X-ray was performed in all patients, in indicated cases also an MRI scan was done, and in more severe cases a CT scan was obtained as well. RESULTS The average vertebral body kyphosis in patients with one injured vertebra was 7.3° (range 1.1°-12.5°). The average vertebral body kyphosis in patients with two injured vertebrae was 5.5° (range 2.1°-12.2°). The average vertebral body kyphosis in patients with more than two injured vertebrae was 3.8° (range 0.2°-11.5°). All patients were treated conservatively in line with the proposed protocol. No complications were observed, no deterioration of the kyphotic shape of the vertebral body was reported, no instability occurred, and no surgical intervention had to be considered. DISCUSSION Pediatric spine injuries are in most cases treated conservatively. Surgical treatment is opted for in 7.5-18% of cases, in dependence on the evaluated group of patients, age of the patients and philosophy of the department concerned. In our group, all patients were treated conservatively. CONCLUSIONS 1. To diagnose F0 fractures, two unenhanced orthogonal view X-rays are indicated, whereas MRI examination is not routinely performed. In F1 fractures, an X-ray is indicated, and an MRI scan is considered based on the age and extent of injury. In F2 and F3 fractures, an X-ray is indicated and subsequently the diagnosis is confirmed by MRI, in F3 fractures also a CT scan is performed. 2. In young children (under 6 years of age), in whom an MRI procedure would require general anaesthesia, MRI is not routinely performed. 3. In F0 fractures, crutches or a brace are not indicated. In F1 fractures, verticalization using crutches or a brace is considered in dependence on the patient's age and extent of injury. In F2 fractures, verticalization using crutches or a brace is indicated. 4. In F3 fractures, surgical treatment is considered, followed by verticalization using crutches or a brace. In case of conservative treatment, the same procedures as in F2 fractures are applied. 5. Long-term bed rest is contraindicated. 6. Duration of spinal load reduction (restriction of sports activities, or verticalization using crutches or a brace) in F1 injuries is 3-6 weeks based on the age of the patient, it increases with the age, with the minimum being 3 weeks. 7. Duration of spinal load reduction (verticalization using crutches or a brace) in F2 and F3 injuries is 6-12 weeks based on the age of the patient, it increases with the age, with the minimum being 6 weeks. Key words: pediatric spine injury, thoracolumbar compression fractures, children trauma treatment.
- MeSH
- Lumbar Vertebrae diagnostic imaging surgery MeSH
- Child MeSH
- Spinal Fractures * diagnostic imaging etiology MeSH
- Thoracic Vertebrae diagnostic imaging surgery MeSH
- Infant MeSH
- Fractures, Compression * diagnostic imaging etiology MeSH
- Kyphosis * surgery MeSH
- Humans MeSH
- Infant, Newborn MeSH
- Child, Preschool MeSH
- Treatment Outcome MeSH
- Check Tag
- Child MeSH
- Infant MeSH
- Humans MeSH
- Infant, Newborn MeSH
- Child, Preschool MeSH
- Publication type
- English Abstract MeSH
- Journal Article MeSH
