BACKGROUND: Surgical site infection (SSI) is the most consistently reported complication of cranioplasty. No material showed a categorical superiority in the incidence of infection. Porous polyethylene (PE) is considered a low risk material regarding SSI. However, the literature data are very limited. Thus, our objective was to verify the assumed low incidence of SSI after PE cranioplasty in patients at high risk of SSI. The primary objective was the infection rate, while secondary objectives were implant exposure, revision and cosmetic results. METHOD: Patients who underwent three-dimensional (3D) personalized PE cranioplasty in the period 2014-2023 were evaluated prospectively. Only patients with an increased risk of SSI, and a satisfactory clinical conditions were included in the study. RESULTS: Thirty procedures were performed in 30 patients. Cranioplasty was performed 23 times after hemispheric decompressive craniectomy, five times after limited size craniotomy and two times after bifrontal decompressive craniectomy. Risk factors for the development of infection were 18 previous SSIs, 16 previous repeated revision surgeries, four intraoperatively opened frontal sinuses and two times radiotherapy. Neither infection nor implant exposure was detected in any patient. All patients were satisfied with the aesthetic result. In two cases, a revision was performed due to postoperative epidural hematoma. CONCLUSIONS: Three-dimensional personalized PE cranioplasty is associated with an extremely low incidence of SSI even in high-risk patients. However, our conclusions can only be confirmed in larger studies.
- MeSH
- dekompresní kraniektomie škodlivé účinky metody MeSH
- dospělí MeSH
- infekce chirurgické rány * epidemiologie etiologie MeSH
- kraniotomie škodlivé účinky metody MeSH
- lebka chirurgie MeSH
- lidé středního věku MeSH
- lidé MeSH
- polyethylen MeSH
- poréznost MeSH
- prospektivní studie MeSH
- rizikové faktory MeSH
- senioři MeSH
- zákroky plastické chirurgie * metody škodlivé účinky MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: Total knee arthroplasty (TKA) with all-polyethylene tibial (APT) components has shown comparable survivorship and clinical outcomes to that with metal-backed tibial (MBT). Although MBT is more frequently implanted, APT equivalents are considered a low-cost variant for elderly patients. A biomechanical analysis was assumed to be suitable to compare the response of the periprosthetic tibia after implantation of TKA NexGen APT and MBT equivalent. METHODS: A standardised load model was used representing the highest load achieved during level walking. The geometry and material models were created using computed tomography data. In the analysis, a material model was created that represents a patient with osteopenia. RESULTS: The equivalent strain distribution in the models of cancellous bone with an APT component showed values above 1000 με in the area below the medial tibial section, with MBT component were primarily localised in the stem tip area. For APT variants, the microstrain values in more than 80% of the volume were in the range from 300 to 1500 με, MBT only in less than 64% of the volume. CONCLUSION: The effect of APT implantation on the periprosthetic tibia was shown as equal or even superior to that of MBT despite maximum strain values occurring in different locations. On the basis of the strain distribution, the state of the bone tissue was analysed to determine whether bone tissue remodelling or remodelling would occur. Following clinical validation, outcomes could eventually modify the implant selection criteria and lead to more frequent implantation of APT components.
PURPOSE: This study aims to compare total knee replacement (TKA) with NexGen All-Poly (APT) and NexGen Metal-Backed (MBT) in terms of implant survivorship, reasons leading to implant failure and functional results of defined age categories. METHODS: A single-centre, retrospective evaluation of 812 patients who underwent knee replacement with NexGen CR between 2005 and 2021, comparing a modern congruent APT component to a modular MBT equivalent component using a similar surgical technique at a notable mean follow-up duration. Implant survival, functional outcomes using the Knee Society Score and range of motion were evaluated and compared in different age categories. RESULTS: Of the 812 NexGen CR TKAs performed at our institution, 410 (50.4%) used APT components and 402 (49.6%) MBT components. The survival rate of NexGen APT was 97.1% and that of NexGen MBT was 93.2% (p = 0.36). Removal of the implant occurred overall in 15 cases, for MBT in ten cases, and for APT in four cases. The FS was proved to be significantly higher when APT components were implanted in younger patients than for MBT (p = 0.005). A similar range of motion between the components was recorded (p = 0.1926). CONCLUSION: Under defined conditions, we measured the clinical results of implants from a single manufacturer implanted in a single department using a similar surgical technique. Considering the limitations, we suggest that all-polyethylene tibial components are equal or even superior to metal-backed ones across the examined age categories.
- MeSH
- kovy MeSH
- lidé MeSH
- polyethylen MeSH
- protézy - design MeSH
- protézy kolene * MeSH
- retrospektivní studie MeSH
- totální endoprotéza kolene * škodlivé účinky MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Cíl: Kranioplastika je dle literatury zatížena až 50% rizikem vzniku komplikací. Mezi nejčastější patří ranná infekce. Porózní polyethylen je považován za alogenní materiál s nejnižším výskytem infekce. Cílem práce bylo ověření předpokládaného nízkého výskytu ranné infekce po implantaci porózního polyethylenu i v rizikovém terénu. Sekundárním cílem bylo posouzení uvolnění implantátu fixovaného pomocí minidlah a obnažení implantátu. Metodika: Prospektivně jsme sledovali a hodnotili skupinu 12 nemocných, u kterých byla v období 2014–2021 provedena na míru počítačově modelovaná 3D kranioplastika z porózního polyethylenu v rizikovém terénu. Rizikový terén byl definován jako předchozí ranná infekce, opakované revizní operace s resorpcí nebo uvolněním kostní ploténky nebo implantátu a otevřený frontální sinus. Výskyt uvedených komplikací byl hodnocen prostřednictvím fyzikálního vyšetření lokálního nálezu a CT. Výsledky: Celkem jsme provedli 12 kranioplastik u 12 nemocných. Průměrný follow-up byl 47 měsíců. V pěti případech byla kranioplastika indikována z důvodu ranné infekce, čtyřikrát po opakovaných revizních operacích s resorpcí nebo uvolněním kostní ploténky nebo implantátu a ve třech případech kvůli otevřenému frontálnímu sinu. Osm pacientů mělo kombinaci dvou rizikových faktorů. U žádného nemocného nebyla po kranioplastice zaznamenána ranná infekce. Ve všech případech byla fixace minidlahami dostatečná a u žádného nemocného nebylo zaznamenáno obnažení implantátu. Závěr: V našem souboru jsme potvrdili vysokou spolehlivost porózního polyethylenu z pohledu minimálního rizika ranné infekce i v rizikovém terénu.
Aim: According to the literature, cranioplasty is associated with up to 50% risk of complications. The most common complication is wound infection. Porous polyethylene is considered to be an allogenic material with the lowest rate of infection. The aim of this study was to verify the assumed low rate of wound infections after implantation of porous polyethylene, even in high-risk terrain. The secondary objective was to assess the loosening of the implant fixed with mini-plates and the exposure of the implant. Methods: A group of 12 patients who underwent a customized computer-modeled 3D cranioplasty from porous polyethylene in a high-risk terrain was followed prospectively between 2014 and 2021. The high-risk terrain was defined as a previous wound infection, repeated surgeries with resorption or loosening of the bone or an implant and an open frontal sinus. The occurrence of listed complications was evaluated through physical examination and CT. Results: In total, there were 12 cranioplasties performed in 12 patients. The average follow-up period was 47 months. In five cases, cranioplasty was indicated after an wound infection, four times after repeated surgeries with the resorption or loosening of the bone or implant, and in three cases in the terrain of the open frontal sinus. Eight patients had a combination of two risk factors. No patient had wound infection after cranioplasty. In all cases, fixation with mini-plates was sufficient, and no implant was exposed. Conclusion: Our study confirmed high reliability and low risk of wound infection of porous polyethylene, even in a high-risk terrain.
- Klíčová slova
- kranioplastika,
- MeSH
- 3D tisk MeSH
- alografty MeSH
- dekompresní kraniektomie * MeSH
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- plastická chirurgie MeSH
- polyethylen * terapeutické užití MeSH
- pooperační komplikace prevence a kontrola MeSH
- prospektivní studie MeSH
- senioři MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
Greater wax moth (GWM), Galleria mellonella (Lepidoptera: Pyralidae), is a highly destructive honey bee pest prevalent throughout the world. It is considered as a major factor to the alarming decline in honey bee population. GWM destroys active honey combs as it feeds on the beeswax and lays eggs in bee hives, and the primary food of their larva is beeswax. Beeswax is a polymer composed mainly of saturated and unsaturated, linear and complex monoesters, and hydrocarbons. The most frequent bond in beeswax is ethene (CH2-CH2) which is also found in the common plastic polyethylene. As wax-digestion is not a common animal character, we hypothesized about a possible role of GWM gut microflora in the process; which could possibly degrade polyethylene-like polymers as well. This study was aimed to identify the GWM gut microflora via culture-dependant approach. We characterized several bacterial species based on the culture characteristics, Gram-reaction, and various biochemical tests. Sequencing of 16S-rDNA revealed nine bacterial and one microalgal species from GWM gut. The bacterial species included Gram-positive Exiguobacterium aestuarii, Bacillus circulans, Microbacterium zaea, Microbacterium sp. and Enterococcus faecalis; Gram-negative Agrobacterium sp., Sphingomonas pseudosanguinis, Sphingobium yanoikuyae and Acinetobacter radioresistens; the microalgae was Picochlorum oklahomensis. Some of them have been previously reported to degrade polycyclic aromatic hydrocarbon, low-density polyethylene, and 2-methylphenanthrene. Meanwhile, the microalga, P. oklahomensis, was reported to steal bacterial genes to adapt with abiotic stresses. Further investigation is necessary to explore the precise details about polymer degrading capabilities of these microbes; nevertheless, this study builds a foundation for elaborate and advanced future research.
BACKGROUND AND OBJECTIVE: Total knee arthroplasty (TKA) with modern all-polyethylene tibial (APT) components has shown high long-term survival rates and comparable results to those with metal-backed tibial components. Nevertheless, APT components are primarily recommended for older and low-demand patients. There are no evidence-based biomechanical guidelines for orthopaedic surgeons to determine the appropriate lower age limit for implantation of APT components. A biomechanical analysis was assumed to be suitable to evaluate the clinical results in patients under 70 years. The scope of this study was to determine biomechanically the appropriate lower age limit for implantation of APT components. METHODS: To generate data of the highest possible quality, the geometry of the computational models was created based on computed tomography (CT) images of a representative patient. The cortical bone tissue model distinguishes the change in mechanical properties described in three parts from the tibial cut. The cancellous bone material model has a heterogeneous distribution of mechanical properties. The values used to determine the material properties of the tissues were obtained from measurements of a CT dataset comprising 45 patients. RESULTS: Computational modeling showed that in the majority of the periprosthetic volume, the von Mises strain equivalent ranges from 200 to 2700 με; these strain values induce bone modeling and remodeling. The highest measured deformation value was 2910 με. There was no significant difference in the induced mechanical response between bone models of the 60-year and 70-year age groups, and there was <3% difference from the 65-year age group. CONCLUSIONS: Considering in silico limitations, we suggest that APT components could be conveniently used on a bone with mechanical properties of the examined age categories. Under defined loading conditions, implantation of TKA with APT components is expected to induce modeling and remodeling of the periprosthetic tibia. Following clinical validation, the results of our study could modify the indication criteria of the procedure, and lead to more frequent implantation of all-polyethylene TKA in younger patients.
- MeSH
- analýza metodou konečných prvků MeSH
- biomechanika MeSH
- kovy MeSH
- lidé MeSH
- mechanický stres MeSH
- polyethylen MeSH
- protézy - design MeSH
- protézy kolene * MeSH
- tibie diagnostické zobrazování chirurgie MeSH
- totální endoprotéza kolene * metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
PURPOSE OF THE STUDY Use of an all-polyethylene (all-poly, AP) tibial component in primary total knee arthroplasty is still an attractive option considering the durability of replacement, the elimination of backside wear and the lower cost compared to modular metalbacked tibia. The purpose of the study was to evaluate the long-term results of the total knee replacement using the P.F.C. Sigma system with a monoblock all-polyethylene tibial component implanted at the 1st Orthopedic Department of the St. Anne's University Hospital and Masaryk University Brno in the period 1999-2010. MATERIAL AND METHODS In the monitored period, 911 total knee replacements using P.F.C. Sigma with an all-polyethylene tibial component were performed. This cohort of patients was evaluated at least 10 years after the primary replacement surgery. Altogether 323 knee replacements in 289 patients were evaluated. The clinical outcomes were assessed according to the Knee Society Clinical Rating System (KSS) and the Total Knee Arthroplasty Roentgenographic Evaluation and Scoring System. The replacement survival was evaluated using the Kaplan-Meier survival analysis. RESULTS In the evaluated group, the average KS was 82.6 points and the average functional score was 74.7 points. Excellent results were recorded in 213 cases, good results in 78 and satisfactory in 23 replacements. Poor clinical results were reported in 9 patients. The average range of motion was 105.8°. In 5 knees (1.5%) revision surgery was performed for infection complications, 3 cases were complicated due to periprosthetic fractures, 4 replacements were revised due to anterior knee pain and 8 knees showed a limited range of motion. Only 1 replacement was revised for aseptic loosening, with no need for reimplantation of the component. The survivorship of the implant was 98.5 % at the follow-up of 12.8 years, including the reasons of reimplantation. DISCUSSION Total knee replacement with an all-polyethylene tibial component is not so popular as the metal-backed modular implants. The all-polyethylene tibial component has certain advantages: lower unit costs, no backside wear, no liner dislocation, possibility of conservative bone resection. On the other hand, this type of implant is not modular and augmentations or longer stems cannot be used. Even though this type of endoprosthesis is recommended exclusively for elderly patients with a lower level of activity, the current mid- and long-term results show that indications for all-poly implants are much broader. CONCLUSIONS The total knee replacement with an all-polyethylene tibial component shows very good long-term clinical outcomes with an excellent survival rate. The all-poly design is cost-effective and may be used not only in elderly patients. Key words: total knee replacement, all-polyethylene tibial component, long-term results.
Due to the fact that plastic pollution is a global environmental problem of modern age, studies on the impact of these synthetic materials on aquatic, and especially fish organisms, are an important part of the ecosystem and human nutrition. In our study, the toxicity of pristine polyethylene (PE) microparticles (approx. 50 μm) on rainbow trout (Oncorhynchus mykiss) was tested in three different dietary concentrations - 0.5%, 2% and 5%. After six weeks of exposure, various health indices were evaluated. Electron microscopy of the intestine revealed the disintegration of PE particles to <5 μm in size, and thus we concluded that microplastics are able to reach tissues. The haematological profile revealed changes in total red blood cells count and haematocrit (5% PE) which could be associated with spleen congestion observed histologically. The marker of lipid peroxidation was increased in gills suggesting the disruption of balance in antioxidant enzymes capacity and histopathological imaging revealed inflammation in higher PE concentrations. In addition, ammonia was decreased and calcium elevated in biochemical profile, confirming the gill damage. Electron microscopy of the gills showed lesions of lamellae and visible rings around the mucinous cell opening indicating their higher activity. Another injured was the liver tissue, as confirmed by hepatodystrophies and increased expression of pro-inflammatory genes in 2% PE. Impaired innate immunity was confirmed by an increased presence of mucinous cells and a decrease in leukocytes. Kidney damage manifested itself by higher expression of pro-inflammatory cytokines and histopathology. The damage in gills, liver and kidney together correlated with the increased antioxidant capacity of plasma. In conclusion, PE microparticles are able to affect health indices of O. mykiss. The potential problem for aquatic ecosystems and even human consumption should be considered.
In this work, a novel cation exchange membrane, PSEBS SU22 was deployed in microbial fuel cells (MFCs) to examine system efficacy in line with membrane characteristics and inoculum source. It turned out that compared to a reference membrane (Nafion), employing PSEBS SU22 resulted in higher current density and electricity generation kinetics, while the electron recoveries were similar (19-28%). These outcomes indicated more beneficial ion transfer features and lower mass transfer-related losses in the PSEBS SU22-MFCs, supported by membrane water uptake, ion exchange capacity, ionic conductivity and permselectivity. By re-activating the membranes after (bio)foulant removal, PSEBS SU22 regained nearly its initial conductivity, highlighting a salient functional stability. Although the particular inoculum showed a clear effect on the microbial composition of the membrane biofouling layers, the dominance of aerobic species was revealed in all cases. Considering all the findings, the PSEBS SU22 seems to be promising for application in MFCs.
INTRODUCTION The purpose of our study was to evaluate the clinical outcomes in patients at 3-6 years follow-up after primary implantation of RM Pressfit Vitamys cementless elastic cup and cementless Optimys short stem, including bone tissue remodelling around both the components. MATERIAL AND METHODS The evaluation covered 49 joint replacements in patients who had undergone surgery at our department between 2012 and 2015. The age at the time of primary surgery ranged from 29 to 71 years, with the mean value of 59.2 years. Postoperatively, the position of endoprosthesis, changes in femoroacetabular offset, signs of osseointegration of the implant, bone tissue remodelling around both the components and potential signs of aseptic loosening were assessed. The functional status of the joint was evaluated according to the Harris scale. RESULTS The mean follow-up time of Vitamys cup and Optimys stem was 5.6 years and 4.6 years, respectively. We focused on the combination of RM Pressfit Vitamys (49x), Optimys (28x) and Bionit 2 (41x) implants. All the cups showed good osseointegration. Based on the comparisons with a postoperative X-ray, at least mild osteoporosis in the acetabular roof was confirmed in 6 cases. All Optimys femoral components were in direct contact with the Adams arch and with the endosteal side of lateral cortex of proximal femoral metadiaphysis. Femoroacetabular offset was slightly decreased in 5 patients only. The final evaluation in 2018 did not confirm any radiolucent lines or signs osteolysis around any of the components. In 2 stems only, distal migration less than 2 mm was obvious, with subsequent good osseointegration. Signs of stress shielding were present in 2 femoral components in the form of mild cortical atrophy in the region of the Adams arch. Distal femoral cortical hypertrophy was not observed, the greater trochanter did not show the loss of bone tissue in any of the patients. There were no signs of polyethylene wear. The mean value of HHS increased from 53 to 97 points. An excellent result was achieved in 44 total hip replacements, of which 100 points in 28 cases. In the remaining 5 patients the result was good. The survival rate of both the components was 100% according to the Kaplan-Meier analysis. DISCUSSION The successful functioning of cementless total hip arthroplasty is the correct placement of both components with good primary fixation. Excessive proximal and lateral shift of the centre of rotation results in increased load of endoprosthesis and risk of earlier aseptic loosening, its reduction leads to the weakening of pelvitrochanteric muscles. The shift of the centre of rotation from the original anatomical position should therefore not exceed 5 millimetres. Insufficient cup fixation always results in mechanical failure of an endoprosthesis. Distal migration of stems without contact with external femoral cortex with full weight-bearing of the operated lower extremity in the postoperative period does not constitute a sign of instability, but only its placement enables good osseointegration. Bone remodelling can be assessed by imaging techniques at 2 years after the primary implantation at the earliest. At places with lower load, the bone loss occurs and the loss of bone trabeculae can lead to the failure of fixation of the component. At places with load accumulation, the bone hypertrophy occurs that can be manifested by thigh pain. In case of cementless press-fit cup, the degree of bone remodelling depends on its elasticity, in case of stem on the used material, shape and fixation site. CONCLUSIONS The RM Pressfit Vitamys monobloc cup through its mechanical properties approximates the best the elasticity of bone tissue. The stress distribution around the implant is more symmetrical as against other conventional cementless cups. The Optimys stem enables the reconstruction of anatomical conditions corresponding a healthy hip joint. Respecting the rule of at least three-point fixation is a precondition for good and fast secondary stability of components. Minimising the wear of articulating surfaces and physiological remodelling of adjacent bone tissue are the main factors that help prolong the survivorship of both the components, while also securing more favourable conditions and better outcomes in case of necessity of reimplantation. Key words: cementless elastic cup, short cementless stem, femoroacetabular offset, stress shielding, osseointegration of the implant.
- MeSH
- acetabulum chirurgie MeSH
- kyčelní kloub chirurgie MeSH
- kyčelní protézy * MeSH
- lidé MeSH
- náhrada kyčelního kloubu * MeSH
- následné studie MeSH
- polyethylen MeSH
- protézy - design MeSH
- selhání protézy MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
