The curvature of the lumbar spine plays a critical role in maintaining spinal function, stability, weight distribution, and load transfer. We have developed a mathematical model of the lumbar spine curve by introducing a novel mechanism: minimization of the elastic bending energy of the spine with respect to two biomechanical parameters: dimensionless lumbosacral spinal curvature cLS and dimensionless curvature increment along the spine CI. While most of the biomechanical studies focus on a particular segment of the spine, the distinction of the presented model is that it describes the shape of the thoracolumbar spine by considering it as a whole (non-locally) and thus includes interactions between the different spinal levels in a holistic approach. From radiographs, we have assessed standard geometrical parameters: lumbar lordosis LL, pelvic incidence PI, pelvic tilt PT, sacral slope ψ0 and sagittal balance parameter SB = sagittal vertical axis (SVA)/sacrum-bicoxofemoral distance (SFD) of 42 patients with lumbar spinal stenosis (SS) or degenerative spondylolisthesis (SL) and 21 radiologically normal subjects. SB statistically significantly correlated with model parameters cL5 (r = -0.34, p = 0.009) and -CI (r = 0.33, p = 0.012) but not with standard geometrical parameters. A statistically significant difference with sufficient statistical power between the patients and the normal groups was obtained for cLS, CI, and SB but not for standard geometrical parameters. The model provides a possibility to predict changes in the thoracolumbar spine shape in surgery planning and in assessment of different spine pathologies.
- Publikační typ
- časopisecké články MeSH
Závěrečná zpráva o řešení grantu Agentury pro zdravotnický výzkum MZ ČR
nestr.
Biofilm-related infections (BRI) are an overwhelming issue for health care systems in Europe and worldwide. BRIs are characterized by a chronic behavior or frequent recurrences, antibiotic resistance, complex and prolonged treatment, poor prognosis, high social and economical costs and difficult diagnosis. Demand in implantable biomedical microsystems, which are used for early detection and diagnosis of diseases is increased and lead to intensive research and innovation in such area. However, there a lack of reliable implantable sensors for detection of onset of bacterial infection. Based on the previous knowledge of research team members and preliminary tests, we will design new type of implantable sensors based either on physical or chemical principles of early biofilm detection.
Infekce spojené s tvorbou biofilmu (BRI) jsou zásadním problémem pro zdravotnictví v Evropě i v celosvětovém měřítku. BRI se vyznačují chronickým chováním nebo častými recidivami, rezistencí na antibiotika, komplexní a dlouhodobou léčbou, špatnou prognózou, vysokými sociálními a ekonomickými náklady a obtížnou diagnózou. Požadavky na implantabilní biomedicínské mikrosystémy, které se používají pro včasné odhalení a diagnostiku nemocí, se zvyšují a vedou k jejich intenzivnímu výzkumu a inovacím. Existuje však nedostatek spolehlivých implantabilních senzorů pro včasnou detekci nástupu bakteriální infekce. Na základě předchozích znalostí členů výzkumných týmů a předběžných zkoušek bude navržen nový typ implantabilních senzorů založených buď na fyzikálních, nebo chemických principech včasné detekce vzniku biofilmu.
- Klíčová slova
- detekce biofilmu, implantable biosensors, detection of colonization, detekce infekce, detection of infection, implantovatelný biosenzory,
- NLK Publikační typ
- závěrečné zprávy o řešení grantu AZV MZ ČR
BACKGROUND: The diagnosis of joint replacement infection is a difficult clinical challenge that often occurs when the implant cannot be salvaged. We hypothesize that the pH value of synovial fluid could be an important indicator of the inflammatory status of the joint. However, in the literature, there is a lack of data on the pH changes in hip and knee joint replacements and their relation to infection and implant failure. In this study, we aimed to measure the pH levels of synovial fluid in patients with hip and knee joint replacements. We also investigated the potential of pH measurement as a diagnostic tool for joint replacement infection. In this study, we recorded the pH values to be 7.55 and 7.46 in patients where Pseudomonas aeruginosa was identified as the cause of the prosthetic joint infection. We attribute this to the different environments created by this specific bacterium. In other cases where the pH was higher, chronic mitigated infections were diagnosed, caused by strains of Staphylococcus aureus, Streptococcus agalactiase, and coagulase negative staphylococcus. MATERIALS AND METHODS: In our cohort of 155 patients with implanted hip (THA; n = 85) or knee (TKA; n = 70) joint replacements, we conducted a prospective study with a pH measurement. Out of the whole cohort, 44 patients had confirmed joint replacement infection (28.4%) (44/155). In 111 patients, infection was ruled out (71.6%) (111/155). Joint replacement infection was classified according to the criteria of the Musculoskeletal Infection Society (MSIS) from 2018. Based on the measured values, we determined the cut-off level for the probability of ongoing inflammation. We also determined the sensitivity and specificity of the measurement. RESULTS: The group of patients with infection (n = 44) had a significantly lower synovial fluid pH (pH = 6.98 ± 0.48) than the group of patients with no infection (n = 111, pH = 7.82 ± 0.29, p < 0.001). The corresponding median pH values were 7.08 for the patients with infection and 7.83 for the patients with no infection. When we determined the cut-off level of pH 7.4, the sensitivity level of infected replacements was 88.6%, and the specificity level of the measurement was 95.5%. The predictive value of a positive test was 88.6%, and the predictive value of a negative test was 95.5%. CONCLUSIONS: Our results confirm that it is appropriate to include a pH measurement in the diagnostic spectrum of hip and knee replacements. This diagnostic approach has the potential to provide continuous in vivo feedback, facilitated by specialized biosensors. The advantage of this method is the future incorporation of a pH-detecting sensor into intelligent knee and hip replacements that will assess pH levels over time. By integrating these biosensors into intelligent implants, the early detection of joint replacement infections could be achieved, enhancing proactive intervention strategies.
- Publikační typ
- časopisecké články MeSH
BACKGROUND: Variations observed in biomechanical studies might be attributed to errors made by operators during the construction of musculoskeletal models, rather than being solely attributed to patient-specific geometry. RESEARCH QUESTION: What is the impact of operator errors on the construction of musculoskeletal models, and how does it affect the estimation of muscle moment arms and hip joint reaction forces? METHODS: Thirteen independent operators participated in defining the muscle model, while a single operator performed 13 repetitions to define the muscle model based on 3D bone geometry. For each model, the muscle moment arms relative to the hip joint center of rotation was evaluated. Additionally, the hip joint reaction force during one-legged stance was assessed using static inverse optimization. RESULTS: The results indicated high levels of consistency, as evidenced by the intra- rater and inter-rater agreement measured by the Intraclass Correlation Coefficient (ICC), which yielded values of 0.95 and 0.99, respectively. However, the estimated muscle moment arms exhibited an error of up to 16 mm compared to the reference musculoskeletal model. It was found that muscles attached to prominent anatomical landmarks were specified with greater accuracy than those attached over larger areas. Furthermore, the variability in estimated moment arms contributed to variations of up to 12% in the hip joint reaction forces. SIGNIFICANCE: Both moment arm and muscle force demonstrated significantly lower variability when assessed by a single operator, suggesting the preference for employing a single operator in the creation of musculoskeletal models for clinical biomechanical studies.
- MeSH
- biologické modely MeSH
- biomechanika MeSH
- kosterní svaly * fyziologie MeSH
- kyčelní kloub * fyziologie MeSH
- lidé MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: Approximately, one-third of patients with tumors of proximal humerus will require an extra-articular resection to achieve oncologic margins. This procedure yields poor functional outcomes with a considerable rate of revisions. Unconstrained implants are prone to instability hindering also function of the elbow and hand, whereas constrained shoulder reconstructions suffer from early aseptic loosening of the glenoid component due to bone overload. The purpose of this study was to develop a constrained implant suitable for extra-articular resection with loss of function in deltoid and rotator cuff, which would provide both stability and passive motion, whilst also decreasing the risk of aseptic loosening of the glenoid component. METHODS: In cooperation with Czech Technical University in Prague, we devised an implant consisting of two constrained joints in series connected by a dumbbell piece. The biomechanical analysis showed a reduction of load transfer to the glenoid component with a torque of 8.6 Nm capable of generating an 865-N pulling force on bone screw to just 0.07 Nm, hence shielding the glenoid component from undesired forces and decreasing the risk of aseptic loosening. Three patients with extra-articular resection with a total loss of function of both rotator cuff and deltoid muscle received this type of reconstruction. The average follow-up was 16 months. RESULTS: The surgical technique is straightforward. The surgery took 175 min on average with average blood loss of 516 ml. There were no surgical- or implant-related complications. All three patients were pain-free and had a stable shoulder joint after the reconstruction. All had fully functional elbow, wrist, and hand joints. The average Musculoskeletal Tumor Society (MSTS) score was 21/30 (70%). All patients were pleased with the results. CONCLUSION: The presented innovative implant design has demonstrated to be a promising alternative for reconstruction in these challenging cases.
- MeSH
- humerus MeSH
- lidé MeSH
- lopatka MeSH
- pooperační komplikace etiologie MeSH
- ramenní kloub * chirurgie MeSH
- rameno MeSH
- zákroky plastické chirurgie * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: Mid-term results (clinical and radiographic) of ultra-short anatomical cementless stem total hip arthroplasty (THA) in patients with osteonecrosis of the femoral head (ONFH) has not often been presented. The aim of this study is to evaluate THA using the Proxima stem in patients with ONFH in the mid-term. METHODS: The study consists of 73 patients (97 THAs) with a Proxima stem implanted between 2006 and 2015. The mean age of patients was 47.4 years, with a mean follow-up 105.2 months. The clinical results include preoperative and postoperative Harris Hip Scores (HHSs). Radiological follow-up reports on stem migration, bony trabecular development and radiolucent lines. The complications and revisions were registered. Kaplan-Meier survival analysis was performed to determine the implant survival. RESULTS: The average HHS improved significantly from 40.3 preoperatively to 98.0 at the final evaluation (p ˂ 0.0001). Stem migration (subsidence and "varisation") was observed in 11 hips (in 9 of them up to 6th postoperative month without any further progression, in 2 with progressive migration and radiological loosening). Bony trabecular development was detected in modified Gruen zones (1,2,4,6,7 for Proxima stem): in zone 1 (0%), 2 (67.0%), 4 (64.9%), 6 (64.9%), 7 (0%). Radiolucent lines were observed in 1 cup and 6 stems (2 were loose, 4 with fibrous stable fixation). Complications were found in 5 hips (5.1%): squeezing hip once, repeated dislocation in 1, 1 early deep infection, and 2 loose stems. 2 hips (2.1%) were revised (dislocation, infection). The implant survival was 98.9% and 97.9% clinically and radiologically, respectively. CONCLUSIONS: Observations in the mid-term show that the clinical and radiological results of the Proxima stem in patients with ONFH are promising. The stem design preserves the proximal femoral bone stock. The bony trabecular appearance confirms physiological proximal femoral load transmission.
- MeSH
- hlavice femuru chirurgie MeSH
- kyčelní protézy * MeSH
- lidé středního věku MeSH
- lidé MeSH
- náhrada kyčelního kloubu * škodlivé účinky metody MeSH
- následné studie MeSH
- nekróza hlavice femuru * diagnostické zobrazování chirurgie MeSH
- protézy - design MeSH
- výsledek terapie MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
The coronavirus disease (COVID-19) has significantly affected society, especially healthcare systems worldwide. The aim of this retrospective study is to evaluate the impact of the COVID-19 pandemic on orthopaedic and trauma healthcare at the largest university hospital in the Czech Republic. The evaluated periods were in accordance with three waves of the disease and three respective lockdowns. To correlate the results, we evaluated the number of patients (inpatients and outpatients) treated in the same period in the last 3 years before the pandemic. The number of orthopaedic outpatients during the lockdown period decreased by 54.12% (p = 0.002), 42.88% (p <0.001), and 34.53% (p = 0.03) in the first, second, and third lockdowns, respectively. The number of elective surgeries decreased by 69.01% (p <0.001), 87.57% (p <0.001), and 74.89% (p = 0.007) and the number of acute surgeries decreased by 33.15% (p = 0.002), 37.46% (p <0.001), and 27.24% (p = 0.034) in the first, second, and third lockdowns, respectively. This study showed a significant reduction in the healthcare of orthopaedic and trauma patients owing to the COVID-19 pandemic and emphasised the shortcomings of the healthcare system. In our study, there was a reduction in both outpatient (reduction of care by 24-54%) and inpatient care. The elective surgeries were reduced by 69-87% during different lockdown periods compared with the reference period. Based on the results of this study, we can formulate organisational measures to mitigate the impact of the pandemic on orthopaedic healthcare. Organisational procedures created based on acquired data and experience should maximise the bed capacity of the workplace and work efficiency with regard to the safety of medical staff.
- MeSH
- COVID-19 * epidemiologie MeSH
- kontrola infekčních nemocí MeSH
- lidé MeSH
- ortopedie * MeSH
- pandemie MeSH
- retrospektivní studie MeSH
- SARS-CoV-2 MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
Závěrečná zpráva o řešení grantu Agentury pro zdravotnický výzkum MZ ČR
Nestr.
Ultrahigh molecular weight polyethylene (UHMWPE) is the most common bearing component in total joint replacements (TJR). The polymer exhibits good biocompatibility and high resistance to wear, and its properties can be further optimized. After the year 2000, a number of new commercially available UHMWPE types emerged. Their manufacturers claim that the materials exhibit longer lifetimes both in vitro and in vivo. However, each implant manufacturer promotes its own type of UHMWPE. Comparison of real benefits of the new UHMWPE types is available only from independent studies. We aim at: (i) Development of accelerated (in vitro) aging protocols and comparison of available UHMWPE liners from the point of view of their long-term stability and properties. This should show, which of the new UHMWPE’s will exhibit the best, long-term in vivo performance. (ii) Development of new stabilization/modification methods for UHMWPE as well as for new polymer materials, which should exhibit longer lifetime. This should result in modern types of TJR’s, which will be produced by local manufacturers.
Ultravysokomolekulární polyethylen (UHMWPE) je materiál, který je užíván k výrobě artikulačních komponent kloubních náhrad. Polymer má výbornou biokompatibilitu a malý otěr, jeho strukturu a vlastnosti lze modifikovat. Po roce 2000 se objevila řada nových typů UHMWPE, které in vitro i in vivo vykazují vyšší odolnosti vůči opotřebení. Každý výrobce implantátů prezentuje přednosti svého materiálu. Reálné údaje o materiálech jsou dostupné pouze z nezávislých studií. Cílem projektu je pokračovat v práci týmu: laboratorně připravené i komerční modifikované UHMWPE vystavit prostředí urychleného stárnutí vlastní metodou. Po expozici, odpovídající funkci in vivo po mnoho let, sledovat změny struktury. Výstupem bude informace, které z nyní zaváděných materiálů budou spolehlivé i v dlouhé perspektivě. Jak jsme prokázali, vlastnosti UHMWPE se průběžně zásadně mění. Druhou linií bude hledání nových typů úprav UHMWPE a dalších polymerních materiálů, které by mohly starší typy UHMWPE nahradit. Výstupem by měly být nové typy náhrad, které bude možno vyrábět v ČR a udržet krok s vývojem ve světě.
- MeSH
- artroplastiky kloubů MeSH
- biokompatibilní materiály analýza terapeutické užití MeSH
- polyethylen analýza terapeutické užití MeSH
- protézy kloubů MeSH
- selhání protézy MeSH
- testování materiálů MeSH
- Konspekt
- Patologie. Klinická medicína
- NLK Obory
- technika lékařská, zdravotnický materiál a protetika
- ortopedie
- NLK Publikační typ
- závěrečné zprávy o řešení grantu AZV MZ ČR
Aim: To evaluate the impact of a nanostructured surface created on β-titanium alloy, Ti-36Nb-6Ta, on the growth and differentiation of human mesenchymal stem cells. Materials & methods: The nanotubes, with average diameters 18, 36 and 46 nm, were prepared by anodic oxidation. Morphology, hydrophilicity and mechanical properties of the nanotube layers were characterized. The biocompatibility and osteogenic potential of the nanostructured surfaces were established using various in vitro assays, scanning electron microscopy and confocal microscopy. Results: The nanotubes lowered elastic modulus close to that of bone, positively influenced cell adhesion, improved ALP activity, synthesis of type I collagen and osteocalcin expression, but diminished early cell proliferation. Conclusion: Nanostructured Ti-36Nb-6Ta with nanotube diameters 36 nm was the most promising material for bone implantation.
BACKGROUND CONTEXT: Ligamentum flavum (LF) induced lumbar spinal stenosis (LSS) is conditioned not only by its "gathering" but especially by hypertrophy. Previous studies have examined the pathophysiology and biochemical changes that cause the hypertrophy. Some studies have described a link between chronic LF inflammation and neovascularization but others have reported highly hypovascular LF tissue in LSS patients. Currently, there is no practical application for our knowledge of the pathophysiology of the LF hypertrophy. Considerations for future treatment include influencing this hypertrophy at the level of tissue mediators, which may slow the development of LSS. To our knowledge, there is no study of micromechanical properties of native LF to date. PURPOSE: (1) To clarify the changes in vascularization, chondroid metaplasia, and the presence of inflammatory cell infiltration in LF associated with LSS. (2) To quantify changes in the micromechanical properties associated with LF degenerative processes. STUDY DESIGN/SETTING: Vascular density analysis of degenerated and healthy human LF combined with measurement of micromechanical properties. METHODS: The study involved 35 patients who underwent surgery between November 1, 2015 and October 1, 2016. The LSS group consisted of 20 patients and the control group consisted of 15 patients. LF samples were obtained during the operation and were used for histopathological and nanoindentation examinations. Sample vascularization was examined as microvascular density (Lv), which was morphometrically evaluated using semiautomatic detection in conjunction with NIS-Elements AR image analysis software. Samples were also histologically examined for the presence of chondroid metaplasia and inflammation. Mechanical properties of native LF samples were analyzed using the Hysitron TI 950 TriboIndenter nanomechanical testing system. RESULTS: Vascular density was significantly lower in the LSS group. However, after excluding the effect of age, the difference was not significant. There was high association between Lv and age. With each increasing year of age, Lv decreased by 11.5 mm2. Vascular density decreased up to the age of 50. Over the age of 50, changes were no longer significant and Lv appeared to stabilize. No correlation was observed between Lv and the presence of inflammation or metaplasia; however, LSS patients had a significantly increased incidence of chondroid metaplasia and inflammatory signs. The mechanical properties of control group samples showed significantly higher stiffness than those samples obtained from the LSS group. CONCLUSION: This study showed that Lv changes were not dependent on LSS but were age-dependent. Vascular density was found to decrease up to the age of 50. A significantly higher incidence of chondroid metaplasia and inflammation was observed in LSS patients. The mechanical property values measured by nanoindentation showed high microstructural heterogeneity of the tested ligaments. Our results showed that healthy ligaments were significantly stiffer than LSS ligaments. CLINICAL SIGNIFICANCE: Prevention of the loss of LF vascularization during aging may influence stiffness of LF which in turn may slow down the LF degenerative processes and delay onset of LSS.
