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1.
Acta Biomater ; 180: 128-139, 2024 05.
Artículo en Inglés | MEDLINE | ID: mdl-38636789

RESUMEN

Titanium as the leading implant material in locked plating is challenged by polymers such as carbon fiber-reinforced polyetheretherketone (CFR-PEEK), which became the focus of interest of researchers and manufacturers in recent years. However, data on human tissue response to these new implant materials are rare. Osteosynthesis plates and peri­implant soft tissue samples of 16 healed proximal humerus fractures were examined (n = 8 CFR-PEEK, n = 8 titanium). Soft tissue was analyzed by immunohistochemistry and µCT. The entrapped foreign bodies were further examined for their material composition by FTIR. To gain insight into their origin and formation mechanism, explanted and new plates were evaluated by SEM, EDX, profilometry and HR-CT. In the peri­implant soft tissue of the CFR-PEEK plates, an inflammatory tissue reaction was detected. Tissues contained foreign bodies, which could be identified as tantalum wires, carbon fiber fragments and PEEK particles. Titanium particles were also found in the peri­implant soft tissue of the titanium plates but showed a less intense surrounding tissue inflammation in immunohistochemistry. The surface of explanted CFR-PEEK plates was rougher and showed exposed and broken carbon fibers as well as protruding and deformed tantalum wires, especially in used screw holes, whereas scratches were identified on the titanium plate surfaces. Particles were present in the peri­implant soft tissue neighboring both implant materials and could be clearly assigned to the plate material. Particles from both plate materials caused detectable tissue inflammation, with more inflammatory cells found in soft tissue over CFR-PEEK plates than over titanium plates. STATEMENT OF SIGNIFICANCE: Osteosynthesis plates are ubiquitously used in various medical specialties for the reconstruction of bone fractures and defects and are therefore indispensable for trauma surgeons, ENT specialists and many others. The leading implant material are metals such as titanium, but recently implants made of polymers such as carbon fiber-reinforced polyetheretherketone (CFR-PEEK) have become increasingly popular. However, little is known about human tissue reaction and particle generation related to these new implant types. To clarify this question, 16 osteosynthesis plates (n = 8 titanium and n = 8 CFR-PEEK) and the overlying soft tissue were analyzed regarding particle occurrence and tissue inflammation. Tissue inflammation is clinically relevant for the development of scar tissue, which is discussed to cause movement restrictions and thus contributes significantly to patient outcome.


Asunto(s)
Benzofenonas , Placas Óseas , Fibra de Carbono , Carbono , Inflamación , Cetonas , Polietilenglicoles , Polímeros , Titanio , Humanos , Cetonas/química , Titanio/química , Titanio/efectos adversos , Polietilenglicoles/química , Polímeros/química , Fibra de Carbono/química , Carbono/química , Masculino , Inflamación/patología , Femenino , Persona de Mediana Edad , Anciano , Adulto
2.
BMC Musculoskelet Disord ; 23(1): 95, 2022 Jan 27.
Artículo en Inglés | MEDLINE | ID: mdl-35086539

RESUMEN

BACKGROUND: Posttraumatic shoulder stiffness remains a problem after proximal humerus fracture (PHF) despite good healing rates. The aim of this pilot study was to determine whether the implant material and overlying soft tissue have an effect on shoulder range of motion (ROM) before and after implant removal (IR). METHODS: 16 patients (mean age 55.2 ± 15.3 (SD) years; 62.5% female) were included who underwent operative treatment with locking plates of either carbon fiber reinforced Polyetheretherketone (PEEK) (PEEKPower® humeral fracture plate, Arthrex, Naples, Florida, USA, n = 8) or titanium alloy (Ti) (Philos®, DePuy Synthes, Johnson & Johnson Medical, Raynham, Massachusetts, USA, n = 8) for PHF. All patients presented with a limited ROM and persistent pain in everyday life after the fracture had healed, whereupon IR was indicated. ROM before and after IR were compared as well as the Constant Score (CS) and the CS compared to the contralateral shoulder (%CS) 1 year after IR. RESULTS: In group PEEK, elevation was 116.3° ± 19.2° pre- and 129.4° ± 23.7° post-IR (p = 0.027). External rotation was 35.0° ± 7.6° pre- and 50.6° ± 21.8° post-IR (p = 0.041). External rotation with the humerus abducted 90° was 38.8° ± 18.1° pre- and 52.5° ± 25.5° post-IR (p = 0.024). In group Ti, elevation was 110.0° ± 34.6° pre- and 133.8° ± 31.1° post-IR (p = 0.011). External rotation with the humerus at rest was 33.8° ± 23.1° pre- and 48.8° ± 18.7° post-IR (p = 0.048). External rotation with the humerus abducted 90° was 40.0° ± 31.6° pre- and 52.5° ± 22.5° post-IR (p = 0.011). Comparison of the two implant materials showed no significant difference. The overall CS was 90.3 ± 8.8, the %CS was 91.8% ± 14.7%. CONCLUSION: There was no significant difference in ROM, CS and %CS with respect to plate materials, although lower cell adhesion is reported for the hydrophobic PEEK. However, all patients showed improved functional outcomes after IR in this pilot study. In patients with shoulder stiffness following locked plating for PHF, implants should be removed and open arthrolysis should be performed, independently from the hardware material. LEVEL OF EVIDENCE: II.


Asunto(s)
Fracturas del Hombro , Titanio , Adulto , Anciano , Benzofenonas , Placas Óseas , Femenino , Fijación Interna de Fracturas , Humanos , Húmero/diagnóstico por imagen , Húmero/cirugía , Masculino , Persona de Mediana Edad , Proyectos Piloto , Polímeros , Estudios Retrospectivos , Hombro , Fracturas del Hombro/diagnóstico por imagen , Fracturas del Hombro/cirugía , Resultado del Tratamiento
3.
J Biomed Mater Res B Appl Biomater ; 106(2): 705-715, 2018 02.
Artículo en Inglés | MEDLINE | ID: mdl-28323392

RESUMEN

After implantation of an internal fracture fixation device, blood contacts the surface, followed by protein adsorption, resulting in either soft-tissue adhesion or matrix adhesion and mineralization. Without protein adsorption and cell adhesion under the presence of micro-motion, fibrous capsule formation can occur, often surrounding a liquid filled void at the implant-tissue interface. Clinically, fibrous capsule formation is more prevalent with electropolished stainless steel (EPSS) plates than with current commercially pure titanium (cpTi) plates. We hypothesize that this is due to lack of micro-discontinuities on the standard EPSS plates. To test our hypothesis, four EPSS experimental surfaces with varying microtopographies were produced and characterized for morphology using the scanning electron microscope, quantitative roughness analysis using laser profilometry and chemical analysis using X-ray photoelectron spectroscopy. Clinically used EPSS (smooth) and cpTi (microrough) were included as controls. Six plates of each type were randomly implanted, one on both the left and right intact tibia of 18 white New Zealand rabbits for 12 weeks, to allow for a surface interface study. The results demonstrate that the micro-discontinuities on the upper surface of internal steel fixation plates reduced the presence of liquid filled voids within soft-tissue capsules. The micro-discontinuities on the plate under-surface increased bony integration without the presence of fibrous tissue interface. These results support the hypothesis that the fibrous capsule and the liquid filled void formation occurs mainly due to lack of micro-discontinuities on the polished smooth steel plates and that bony integration is increased to surfaces with higher amounts of micro-discontinuities. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 705-715, 2018.


Asunto(s)
Huesos/metabolismo , Implantes Experimentales , Fijadores Internos , Acero , Animales , Femenino , Conejos , Propiedades de Superficie
4.
Acta Biomater ; 54: 386-398, 2017 05.
Artículo en Inglés | MEDLINE | ID: mdl-28286037

RESUMEN

Fabrication of composite scaffolds using stereolithography (SLA) for bone tissue engineering has shown great promises. However, in order to trigger effective bone formation and implant integration, exogenous growth factors are commonly combined to scaffold materials. In this study, we fabricated biodegradable composite scaffolds using SLA and endowed them with osteopromotive properties in the absence of biologics. First we prepared photo-crosslinkable poly(trimethylene carbonate) (PTMC) resins containing 20 and 40wt% of hydroxyapatite (HA) nanoparticles and fabricated scaffolds with controlled macro-architecture. Then, we conducted experiments to investigate how the incorporation of HA in photo-crosslinked PTMC matrices improved human bone marrow stem cells osteogenic differentiation in vitro and kinetic of bone healing in vivo. We observed that bone regeneration was significantly improved using composite scaffolds containing as low as 20wt% of HA, along with difference in terms of osteogenesis and degree of implant osseointegration. Further investigations revealed that SLA process was responsible for the formation of a rich microscale layer of HA corralling scaffolds. To summarize, this work is of substantial importance as it shows how the fabrication of hierarchical biomaterials via surface-enrichment of functional HA nanoparticles in composite polymer stereolithographic structures could impact in vitro and in vivo osteogenesis. STATEMENT OF SIGNIFICANCE: This study reports for the first time the enhance osteopromotion of composite biomaterials, with controlled macro-architecture and microscale distribution of hydroxyapatite particles, manufactured by stereolithography. In this process, the hydroxyapatite particles are not only embedded into an erodible polymer matrix, as reported so far in the literature, but concentrated at the surface of the structures. This leads to robust in vivo bone formation at low concentration of hydroxyapatite. The reported 3D self-corralling composite architecture provides significant opportunities to develop functional biomaterials for bone repair and tissue engineering.


Asunto(s)
Células de la Médula Ósea/patología , Regeneración Ósea/efectos de los fármacos , Durapatita , Células Madre Mesenquimatosas/metabolismo , Nanopartículas/química , Osteogénesis/efectos de los fármacos , Cráneo , Andamios del Tejido/química , Animales , Células de la Médula Ósea/metabolismo , Durapatita/química , Durapatita/farmacología , Femenino , Humanos , Células Madre Mesenquimatosas/patología , Conejos , Cráneo/lesiones , Cráneo/metabolismo , Cráneo/patología
5.
Eur Cell Mater ; 31: 236-49, 2016 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-27062725

RESUMEN

Pericyte recruitment is essential for the stability of newly formed vessels. It was also suggested that pericytes represent common ancestor cells giving rise to mesenchymal stem cells (MSCs) in the adult. Here, we systematically investigated pericytes and MSCs from different human tissues in terms of their angiogenic and multilineage differentiation potential in vitro in order to assess the suitability of the different cell types for the regeneration of vascularised tissues. Magnetic-activated cell sorting (MACS®) was used to enrich CD34-CD146+ pericytes from adipose tissue (AT) and bone marrow (BM). The multilineage potential of pericytes was assessed by testing their capability to differentiate towards osteogenic, adipogenic and chondrogenic lineage in vitro. Pericytes and endothelial cells were co-seeded on Matrigel™ and the formation of tube-like structures was examined to study the angiogenic potential of pericytes. MSCs from AT and BM were used as controls. CD34-CD146+ cells were successfully enriched from AT and BM. Only BM-derived cells exhibited trilineage differentiation potential. AT-derived cells displayed poor chondrogenic differentiation upon stimulation with transforming growth factor-ß1. Interestingly, osteogenic differentiation was more efficient in AT-PC and BM-PC compared to the respective full MSC population. Matrigel™ assays revealed that pericytes from all tissues integrated into tube-like structures. We show that MACS®-enriched pericytes from BM and AT have the potential to regenerate tissues of different mesenchymal lineages and support neovascularisation. MACS® represents a simple enrichment strategy of cells, which is of particular interest for clinical application. Finally, our results suggest that the regenerative potential of pericytes depends on their tissue origin, which is an important consideration for future studies.


Asunto(s)
Linaje de la Célula/fisiología , Plasticidad de la Célula/fisiología , Células Madre Mesenquimatosas/citología , Neovascularización Fisiológica/fisiología , Pericitos/citología , Adipocitos/citología , Tejido Adiposo/citología , Antígenos CD34/metabolismo , Antígeno CD146/metabolismo , Diferenciación Celular , Células Cultivadas , Condrocitos/citología , Femenino , Células Endoteliales de la Vena Umbilical Humana/citología , Humanos , Osteocitos/citología , Pericitos/fisiología , Placenta/citología , Embarazo , Regeneración/fisiología , Retina/citología
6.
J Biomech ; 47(14): 3509-16, 2014 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-25278045

RESUMEN

Cementless surface replacement arthroplasty (CSRA) of the shoulder was designed to preserve the individual anatomy and humeral bone stock. A matter of concern in resurfacing implants remains the stress shielding and bone remodeling processes. The bone remodeling processes of two different CSRA fixation designs, conical-crown (Epoca RH) and central-stem (Copeland), were studied by three-dimensional (3-D) finite element analysis (FEA) as well as evaluation of contact radiographs from human CSRA retrievals. FEA included one native humerus model with a normal and one with a reduced bone stock quality. Compressive strains were evaluated before and after virtual CSRA implantation and the results were then compared to the bone remodeling and stress-shielding pattern of eight human CSRA retrievals (Epoca RH n=4 and Copeland n=4). FEA revealed for both bone stock models increased compressive strains at the stem and outer implant rim for both CSRA designs indicating an increased bone formation at those locations. Unloading of the bone was seen for both designs under the central implant shell (conical-crown 50-85%, central-stem 31-93%) indicating high bone resorption. Those effects appeared more pronounced for the reduced than for the normal bone stock model. The assumptions of the FEA were confirmed in the CSRA retrieval analysis which showed bone apposition at the outer implant rim and stems with highly reduced bone stock below the central implant shell. Overall, clear signs of stress shielding were observed for both CSRAs designs in the in vitro FEA and human retrieval analysis. Especially in the central part of both implant designs the bone stock was highly resorbed. The impact of these bone remodeling processes on the clinical outcome as well as long-term stability requires further evaluation.


Asunto(s)
Artroplastia de Reemplazo/métodos , Remodelación Ósea/fisiología , Análisis de Elementos Finitos , Articulación del Hombro/fisiología , Articulación del Hombro/cirugía , Estrés Mecánico , Anciano , Anciano de 80 o más Años , Artroplastia de Reemplazo/instrumentación , Densidad Ósea/fisiología , Resorción Ósea/fisiopatología , Fuerza Compresiva/fisiología , Femenino , Humanos , Húmero/fisiopatología , Húmero/cirugía , Prótesis Articulares , Masculino , Persona de Mediana Edad , Modelos Biológicos
7.
J Mater Sci Mater Med ; 24(9): 2195-200, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23838879

RESUMEN

Two different imaging techniques used to determine bone tissue response to dental implants were compared. Dental implants were implanted into the maxillae of 18 pigs, which were sacrificed after 4, 8 and 12 weeks. Implants with surrounding bone tissue were retrieved for methyl methacrylate histology and contact radiography. On identical sections peri-implant bone density and bone implant contact (BIC) ratio were assessed with two different imaging methods. Evaluation of Giemsa eosin stained and contact radiographed sections showed direct osseous integration for all implants and both methods showed a strong correlation with correlation coefficient r = 0.930 (P < 0.0001) for peri-implant bone density and r = 0.817 (P < 0.0001) for bone implant contact ratio. While the two imaging methods showed moderate differences for peri-implant bone density there were significant differences between the BIC values determined. In general, contact radiography tends to underestimate BIC for approximately 4.5 % (P = 0.00003).


Asunto(s)
Implantes Dentales , Oseointegración , Animales , Femenino , Porcinos , Porcinos Enanos
8.
Scand J Med Sci Sports ; 22(1): 12-7, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-20561281

RESUMEN

We analyzed the immunohistochemical labeling patterns of the extracellular matrix of the coracoclavicular ligaments (CCL) in order to relate the molecular composition of the attachment sites to their mechanical environment. Ligaments were exposed from 12 fresh-frozen human cadaveric samples (four males, mean age: 48.6 ± 12.1 years). Cryosection of methanol-fixed and decalcified tissue was cut and sections were labeled with a panel of monoclonal antibodies directed against collagens, proteoglycans and proteins of vascular components. Attachment sites of both ligaments showed characteristic fibrocartilaginous labeling of collagen type II, aggrecan and link protein in all samples. Labeling for type II collagen was most conspicuous at the insertion of the coracoid process. Morphometry of adjacent samples revealed a fibrocartilage zone of 10-15% in relationship with the ligament proper, where labeling for type II collagen, aggrecan and link protein was negative. The presence of fibrocartilage at both entheses of the trapezoid and conoid ligament suggests that the CCL complex is subject to shear/compression forces. A variable fibrocartilage differentiation at the entheses of both ligaments may be related to the marked change in loading and insertion angle that the ligaments undergo during shoulder movement.


Asunto(s)
Matriz Extracelular/química , Ligamentos/anatomía & histología , Ligamentos/química , Adulto , Agrecanos/análisis , Fenómenos Biomecánicos/fisiología , Cadáver , Clavícula , Colágeno Tipo II/análisis , Proteínas de la Matriz Extracelular/análisis , Femenino , Fibrocartílago/anatomía & histología , Fibrocartílago/química , Humanos , Inmunohistoquímica , Ligamentos/irrigación sanguínea , Masculino , Persona de Mediana Edad , Proteoglicanos/análisis , Escápula , Hombro/irrigación sanguínea , Hombro/fisiología
9.
Clin Oral Implants Res ; 23(3): 281-6, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-21806681

RESUMEN

OBJECTIVES: To compare the bone tissue response to surface-modified zirconia (ZrO2 ) and titanium implants. METHODS: Cylindrical low-pressure injection moulded zirconia (ZrO2 ) implants were produced with an acid-etched surface. Titanium implants with identical shape, sandblasted and acid-etched surface (SLA) served as controls. Eighteen adult miniature pigs received both implant types in the maxilla 6 months after extraction of the canines and incisors. The animals were euthanized after 4, 8 and 12 weeks and 16 zirconia and 18 titanium implants with the surrounding tissue were retrieved, embedded in methylmethacrylate and stained with Giemsa-Eosin. The stained sections were digitized and histomorphometrically analysed with regard to peri-implant bone density (bone volume/total volume) and bone-implant contact (BIC) ratio. Statistical analysis was performed using Mann-Whitney' U-test. RESULTS: Histomorphometrical analysis showed direct osseous integration for both materials. ZrO2 implants revealed mean peri-implant bone density values of 60.4% (SD ± 9.9) at 4 weeks, 65.4% (SD ± 13.8) at 8 weeks, and 63.3% (SD ± 21.5) at 12 weeks after implantation, whereas Ti-SLA implants demonstrated mean values of 61.1% (SD ± 6.2), 63.6% (SD ± 6.8) and 68.2% (SD ± 5.8) at corresponding time intervals. Concerning the BIC ratio, the mean values for ZrO(2) ranged between 67.1% (SD ± 21.1) and 70% (SD ± 14.5) and for Ti-SLA between 64.7% (SD ± 9.4) and 83.7% (SD ± 10.3). For the two parameters investigated, no significant differences between both types of implants could be detected at any time point. CONCLUSION: The results indicate that there was no difference in osseointegration between ZrO2 implants and Ti-SLA controls regarding peri-implant bone density and BIC ratio.


Asunto(s)
Implantación Dental Endoósea/métodos , Implantes Dentales , Maxilar/cirugía , Titanio , Circonio , Grabado Ácido Dental , Animales , Densidad Ósea , Diseño de Prótesis Dental , Femenino , Oseointegración , Coloración y Etiquetado , Estadísticas no Paramétricas , Propiedades de Superficie , Porcinos , Porcinos Enanos
10.
Unfallchirurg ; 114(5): 424-30, 2011 May.
Artículo en Alemán | MEDLINE | ID: mdl-21448676

RESUMEN

BACKGROUND: In cases of distal radius fractures information about the regional distribution of cancellous bone is essential for adequate fixation of osteosynthesis material. MATERIALS AND METHODS: Using quantitative computed tomography (qCT) measurements 12 distal radii were divided into 2 groups (good and bad bone quality). High-resolution CT scans were obtained at 13 locations (1-40 mm distant from radial styloid processes). The resulting cross-sections were divided into 4 quadrants and the cancellous bone density was assessed in each of them. RESULTS: In both groups regional cancellous bone density was highest immediately beneath the joint surface and decreased towards the metaphyseal region. Comparing the radial with the ulnar quadrants significant differences were found between distances of 4 mm and 12 mm from the joint surface in both groups. The comparison of the palmar and the dorsal quadrants resulted in an almost identical cancellous bone distribution. CONCLUSION: In osteoporotic distal radii cancellous bone density decrease occurs homogeneously in all regions and is least pronounced beneath the joint surface. Comparing the regional cancellous bone density (radial versus ulnar and palmar versus dorsal) significant differences were mainly found near the joint surface in both groups.


Asunto(s)
Osteoporosis/diagnóstico por imagen , Radio (Anatomía)/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
11.
Z Orthop Unfall ; 148(6): 666-73, 2010 Dec.
Artículo en Alemán | MEDLINE | ID: mdl-20648420

RESUMEN

BACKGROUND: Spinal injuries are common and a standard procedure for the stabilisation of spinal injuries is ventral spondylodesis with an autograft from the iliac crest. Because of the high incidence of harvesting complications there is a need to search for alternative materials. The aim of our study was to evaluate graft integration in the lumbar spine of bovine cancellous bone compared to autologous iliac crest material. MATERIAL AND METHODS: Two groups of eight female adult sheep (median age 3 years, range 2.4-3.8 years) received surgical treatment in the form of anterior monosegmental spondylodesis. The spondylodesis was performed in all animals in the motion segment L3/4 through a lateral approach with the animals lying on their right sides. To produce serial sections, the explanted vertebral segments were implanted in methyl methacrylate. On one side the histological preparation was examined qualitatively and in addition we analysed the quantity of the bone structure with special software. RESULTS: The bone structure in both groups did not differ significantly and demonstrated integration of the grafts in the adjacent vertebral bodies. Fractures and lysis occurred in the region of the intervertebral disc and were more frequent in the group with the bovine graft. CONCLUSION: The bony integration of the grafts of both groups was not significantly different and showed good results. Almost all of the bovine grafts fractured or presented regions of lysis. In our opinion bovine cancellous bone graft is not a good alternative to autologous iliac crest.


Asunto(s)
Supervivencia de Injerto/fisiología , Ilion/fisiopatología , Ilion/trasplante , Vértebras Lumbares/fisiopatología , Vértebras Lumbares/cirugía , Fusión Vertebral/instrumentación , Animales , Bovinos , Femenino , Ovinos , Especificidad de la Especie , Resultado del Tratamiento
12.
J Bone Joint Surg Br ; 91(8): 1049-53, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19651832

RESUMEN

In 100 patients the fulcrum axis which is the line connecting the anterior tip of the coracoid and the posterolateral angle of the acromion, was used to position true anteroposterior radiographs of the shoulder. This method was then compared with the conventional radiological technique in a further 100 patients. Three orthopaedic surgeons counted the number of images without overlap between the humeral head and glenoid and calculated the amount of the glenoid surface visible in each radiograph. The analysis was repeated for intraobserver reliability. The learning curves of both techniques were studied. The amount of free visible glenoid space was significantly higher using the fulcrum-axis method (64 vs 31) and the comparable glenoid size increased significantly (8.56 vs 6.47). Thus the accuracy of the anteroposterior radiographs of the shoulder is impaired by using this technique. The intra and interobserver reliability showed a high consistency. No learning curve was observed for either technique.


Asunto(s)
Acromion/diagnóstico por imagen , Contusiones/diagnóstico por imagen , Manguito de los Rotadores/diagnóstico por imagen , Luxación del Hombro/diagnóstico por imagen , Fracturas del Hombro/diagnóstico por imagen , Articulación del Hombro/diagnóstico por imagen , Adulto , Anciano , Anciano de 80 o más Años , Contusiones/complicaciones , Femenino , Humanos , Interpretación de Imagen Asistida por Computador , Masculino , Persona de Mediana Edad , Variaciones Dependientes del Observador , Postura , Radiografía , Lesiones del Manguito de los Rotadores , Articulación del Hombro/anatomía & histología , Adulto Joven
13.
Clin Oral Implants Res ; 20(11): 1247-53, 2009 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19531104

RESUMEN

OBJECTIVES: The purpose of the present study was to histologically compare the bone tissue responses to surface-modified zirconia and titanium implants. METHODS: Threaded zirconia implants were produced using a new low-pressure injection moulding technique and thereafter surface treated by acid etching. Titanium implants with the exact shape and surface treated by sandblasting and acid etching (SLA) served as controls. Fifteen adult pigs received both implant types in the maxilla 6 months after extraction of the second and third incisors. The animals were sacrificed after 4, 8 and 12 weeks and 30 implants with surrounding bone were retrieved. RESULTS: Histological evaluation showed osseous integration for both materials. Zirconia implants revealed mean peri-implant bone density values of 42.3% (SD +/- 14.5) at 4 weeks, 52.6% (SD +/- 5.7) at 8 weeks and 54.6% (SD +/- 11.5) at 12 weeks after implantation, whereas Ti-SLA implants demonstrated mean values of 29% (SD +/- 10), 44.1% (SD +/- 18) and 51.6% (SD +/- 8.6) at corresponding time intervals. With respect to the bone-implant contact ratio, the mean values for zirconia ranged between 27.1% (SD +/- 3.5) and 51.1% (SD +/- 12.4) and for Ti-SLA, it ranged between 23.5% (SD +/- 7.5) and 58.5% (SD +/- 11.4). For the parameters investigated, no statistically significant differences between both types of implants could be detected at any time point. CONCLUSIONS: No statistical difference between implants could be demonstrated with any of the methods used. The limited number of animals per group, however, does not allow to conclude that there is no difference in osseointegration between the two types of implants, although the data tend to suggest such a trend.


Asunto(s)
Implantes Dentales de Diente Único , Diseño de Prótesis Dental , Maxilar/fisiología , Oseointegración/fisiología , Titanio , Circonio , Proceso Alveolar/anatomía & histología , Proceso Alveolar/fisiología , Proceso Alveolar/cirugía , Animales , Densidad Ósea/fisiología , Regeneración Ósea/fisiología , Implantación Dental Endoósea/métodos , Estudios de Seguimiento , Maxilar/anatomía & histología , Maxilar/cirugía , Propiedades de Superficie , Porcinos
14.
J Anat ; 211(1): 1-7, 2007 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-17532798

RESUMEN

The triangular fibrocartilage complex (TFCC) transmits load from the wrist to the ulna and stabilizes the distal radioulnar joint. Damage to it is a major cause of wrist pain. Although its basic structure is well established, little is known of its molecular composition. We have analysed the immunohistochemical labelling pattern of the extracellular matrix of the articular disc and the meniscal homologue of the TFCC in nine elderly individuals (age range 69-96 years), using a panel of monoclonal antibodies directed against collagens, glycosaminoglycans, proteoglycans and cartilage oligomeric matrix protein (COMP). Although many of the molecules (types I, III and VI collagen, chondroitin 4 sulphate, dermatan sulphate and keratan sulphate, the oversulphated epitope of chondroitin 6 sulphate, versican and COMP) were found in all parts of the TFCC, aggrecan, link protein and type II collagen were restricted to the articular disc and to entheses. They were thus not a feature of the meniscal homologue. The shift in tissue phenotype within the TFCC, from a fibrocartilaginous articular disc to a more fibrous meniscal homologue, correlates with biomechanical data suggesting that the radial region is stiff and subject to considerable stress concentration. The presence of aggrecan, link protein and type II collagen in the articular disc could explain why the TFCC is destroyed in rheumatoid arthritis, given that it has been suggested that autoimmunity to these antigens results in the destruction of articular cartilage. The differential distribution of aggrecan within the TFCC is likely to be reflected by regional differences in water content and mobility on the radial and ulnar side. This needs to be taken into account in the design of improved MRI protocols for visualizing this ulnocarpal complex of the wrist.


Asunto(s)
Proteínas de la Matriz Extracelular/análisis , Fibrocartílago Triangular/química , Anciano , Anciano de 80 o más Años , Agrecanos/análisis , Biomarcadores/análisis , Colágeno Tipo I/análisis , Colágeno Tipo III/análisis , Colágeno Tipo VI/análisis , Femenino , Glicosaminoglicanos/análisis , Humanos , Inmunohistoquímica , Masculino , Proteoglicanos/análisis , Radio (Anatomía) , Tenascina/análisis , Fibrocartílago Triangular/ultraestructura , Cúbito , Versicanos/análisis
15.
J Biomech ; 40(5): 1158-64, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-16806236

RESUMEN

The use of artificial bones in implant testing has become popular due to their low variability and ready availability. However, friction coefficients, which are critical to load transfer in uncemented implants, have rarely been compared between human and artificial bone, particularly for wet and dry conditions. In this study, the static and dynamic friction coefficients for four commercially used titanium surfaces (polished, Al(2)O(3) blasted, plasma sprayed, beaded) acting on the trabecular component of artificial bones (Sawbones) were compared to those for human trabecular bone. Artificial bones were tested in dry and wet conditions and normal interface stress was varied (0.25, 0.5, 1.0MPa). Friction coefficients were mostly lower for artificial bones than real bone. In particular, static friction coefficients for the dry polished surface were 20% of those for real bone and 42-61% for the dry beaded surface, with statistical significance (alpha<0.05). Less marked differences were observed for dynamic friction coefficients. Significant but non-systematic effects of normal stress or wet/dry condition on friction coefficients were observed within each surface type. These results indicate that the use of artificial bone models for pre-clinical implant testing that rely on interface load transfer with trabecular bone for mechanical integrity can be particularly sensitive to surface finish and lubrication conditions.


Asunto(s)
Sustitutos de Huesos , Huesos/fisiología , Modelos Anatómicos , Prótesis e Implantes , Fenómenos Biomecánicos/instrumentación , Fenómenos Biomecánicos/métodos , Humanos , Propiedades de Superficie
16.
Z Orthop Ihre Grenzgeb ; 144(5): 539-44, 2006.
Artículo en Alemán | MEDLINE | ID: mdl-16991074

RESUMEN

AIM: The aim of this study was to elucidate whether there is a systemic spread of wear debris from peripherally applied stainless steel and titanium particles into the blood and subsequently to parenchymatous organs. Furthermore, we report on histological findings at the implantation site. METHOD: In Syrian Gold hamsters we implanted 2 mm3 wear debris of stainless steel and titanium into the dorsal skin fold chamber. Over a period of 2 weeks we took blood samples and afterwards explanted the implant area, the heart, lung, liver and spleen. One half of the organs and the implant area were used for histological analysis. The other half of the organs and the blood samples were analysed by optical emission spectrometer with inductively coupled plasma and graphite furnace atomic absorption spectrophotometry for their contents of chromium, nickel and titanium. RESULTS: In the group with titanium particles, histological analysis of the implant site showed moderate phagocyted wear in granulocytes but no other pathological findings. Animals treated with stainless steel wear debris had a massive inflammatory reaction, in some cases leading to necrosis. The analysis of the blood and one half of the organs showed increased levels of chromium and, already 24 hours after implantation, raised values for nickel. The result of the hamsters treated with titanium showed significantly elevated levels of titanium ions in the organs, but not in the blood samples. Histology of the organs did not reveal pathological findings. CONCLUSION: In this study we could show a massive inflammatory reaction for stainless steel wear debris in contrast to titanium wear debris at the implantation site. The elevated blood levels of chromium and increased values of other metals in the organs suggest the haematogenic distribution of ions from the peripherally implanted wear debris.


Asunto(s)
Reacción a Cuerpo Extraño/sangre , Falla de Prótesis , Infecciones Relacionadas con Prótesis/sangre , Acero Inoxidable/efectos adversos , Acero Inoxidable/análisis , Titanio/efectos adversos , Titanio/sangre , Animales , Cricetinae , Reacción a Cuerpo Extraño/etiología , Mesocricetus , Infecciones Relacionadas con Prótesis/etiología
17.
Proc Inst Mech Eng H ; 220(2): 219-27, 2006 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-16669389

RESUMEN

Insufficient understanding of tribological behaviour in total joint arthroplasty is considered as one of the reasons for prosthesis failure. Contrary to the continuous motion input profiles of hip simulators, human locomotion contains motion interruptions. These occurring resting periods can cause stick phenomena in metal-on-metal hip joints. The aim of the present study was to investigate the tribological sensitivity of all-metal bearings to motion interruptions on in vitro test specimens and retrieved implants. Friction and wear with and without resting periods were quantified. Unlike the metal-on-polyethylene joints, the static friction of metal-on-metal joints increased up to micros = 0.3 with rest, while wear appeared to be unaffected. This effect is caused by the interlocking of firmly adhered carbon layers, which were generated from the protein-containing lubricant through tribochemical reactions. Since more than 80 per cent of the retrieved implants exhibited macroscopically visible carbon layers, the increase in friction presumably also occurs under physiological conditions, which is then transferred to the bone-implant interface. These recurrent tangential stress peaks should be considered for the design features of the cup-bone interface, in particular when larger-sized implant heads are used.


Asunto(s)
Materiales Biocompatibles/análisis , Materiales Biocompatibles/química , Prótesis de Cadera , Falla de Prótesis , Vitalio/análisis , Vitalio/química , Análisis de Falla de Equipo/instrumentación , Análisis de Falla de Equipo/métodos , Fricción , Lubrificación , Ensayo de Materiales , Tamaño de la Partícula , Diseño de Prótesis , Propiedades de Superficie , Factores de Tiempo
18.
Biomed Tech (Berl) ; 50(6): 195-200, 2005 Jun.
Artículo en Alemán | MEDLINE | ID: mdl-16003921

RESUMEN

An ongoing unraveling of the molecular mechanisms in aseptic loosening of hip arthroplasty has opened up novel potential pharmacological interventions. In this study the antiresorptive effects of the bisphosphonate zoledronate and the statin simvastatin on ultra high molecular weighted polyethylene (UHMWPE) particle-induced osteolysis were compared. Two previous studies of our group based on the murine calvarial model of UHWMPE particle-induced osteolysis were pooled to form four study groups. Animals in group I (n=14) underwent sham surgery only. In groups II (n=14), III (n=7) and IV (n=7) UHMWPE particles were implanted on the calvariae. Animals in groups III and IV were additionally treated with zoledronate (single 25 microg/kg s.c. injection) and simvastatin (120 mg/day p.o. for 14 days), respectively. After two weeks, calvaria were processed for undecalcified histomorphometry. Bone resorption was measured using Giemsa staining. Osteoclast numbers were determined using TRAP-staining. UHMWPE particle implantation resulted in a grossly pronounced osteolytic activity with significantly increased values of bone resorption (p < 0.001) and osteoclast numbers (p < 0.001). Additional treatment with zoledronate or simvastatin counteracted the particle-induced effects. A comparison of the two medical treatments revealed no statistically significant differences in bone resorption (p = 0.63) and osteoclast numbers (p = 0.41). A single dose of the bisphosphonate zoledronate decreased UHMWPE particle-induced osteolysis in a murine calvarial model as effectively as a daily treatment with simvastin. Both drug groups may have a preventive and therapeutic role as antiresorptive agents in wear particle-induced bone resorption following total joint replacement.


Asunto(s)
Resorción Ósea/patología , Resorción Ósea/prevención & control , Difosfonatos/uso terapéutico , Imidazoles/uso terapéutico , Osteólisis/patología , Osteólisis/prevención & control , Polietilenos/efectos adversos , Simvastatina/uso terapéutico , Animales , Resorción Ósea/etiología , Femenino , Reacción a Cuerpo Extraño/etiología , Reacción a Cuerpo Extraño/patología , Reacción a Cuerpo Extraño/prevención & control , Masculino , Ratones , Ratones Endogámicos C57BL , Osteólisis/etiología , Tamaño de la Partícula , Cráneo/efectos de los fármacos , Cráneo/patología , Resultado del Tratamiento , Ácido Zoledrónico
19.
Z Orthop Ihre Grenzgeb ; 142(3): 366-70, 2004.
Artículo en Alemán | MEDLINE | ID: mdl-15250012

RESUMEN

AIM: The longevity of total hip arthroplasty is sometimes limited by osteolysis and aseptic loosening. Aseptic loosening may be caused by the biologic reaction to polyethylene wear particles. Particles of less than 1 micro m diameter are of particular importance. These particles are not easily available for experimental use. METHOD: We performed a morphologic analysis of commercially available, very small polyethylene particles (Ceridust(R)) in order to determine the specific size distribution. We measured 1 978 particles. Size analysis was performed using an electron microscope. Particle size was described as the equivalent circle diameter (ECD). Particle morphology was described as feret ratio. In addition, Ceridust(R) particles were compared to different particles stemming from a hip simulator experiment. RESULTS: More than 35 % of the particles were less than 1 micro m in size. The particle size was 1.75 micro m +/- 1.43 micro m (median 1.42 micro m). The minimum was 0.06 micro m, the maximum was 11.06 micro m. The feret ratio was 0.58 +/- 0.17 (median 0.63). The minimum was 0.07, the maximum was 0.93. The majority of Ceridust(R) particles had a rough surface. Compared to polyethylene particles stemming from a hip simulator experiment, Ceridust(R) particles had a rougher surface, were less longitudinal, and had a more even size distribution. CONCLUSIONS: The pure, commercially available polyethylene particles analyzed here are suitable for in vitro and in vivo experiments due to their easy availability, minor costs, and large fraction of very small particles.


Asunto(s)
Materiales Biocompatibles/química , Análisis de Falla de Equipo/instrumentación , Análisis de Falla de Equipo/métodos , Ensayo de Materiales/métodos , Microesferas , Polietileno/análisis , Polietileno/química , Tamaño de la Partícula , Propiedades de Superficie
20.
Osteoarthritis Cartilage ; 10(4): 308-20, 2002 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-11950254

RESUMEN

OBJECTIVE: The aim of this study was to examine the effects of recombinant human Fgf18 on chondrocyte proliferation and matrix production in vivo and in vitro. In addition, the expressions of Fgf18 and Fgf receptors (Fgfr) in adult human articular cartilage were examined. METHODS: Adenovirus-mediated transfer of Fgf18 into murine pinnae and addition of FGF18 to primary cultures of adult articular chondrocytes were used to assess the effects of FGF18 on chondrocytes. In situ hybridization was used to examine the expression of Fgf18 and Fgfr s in adult human articular cartilage. RESULTS: Expression of Fgf18 by adenovirus-mediated gene transfer in murine pinnae resulted in a significant increase in chondrocyte number. Chondrocytes were identified by staining with toluidine blue and a monoclonal antibody directed against type II collagen. Fgf18, Fgfr 2-(IIIc), Fgfr 3-(IIIc), and Fgfr 4 mRNAs were detected within these cells by in situ hybridization. The nuclei of the chondrocytes stained with antibodies to PCNA and FGF receptor (FGFR) 2. Addition of FGF18 to the culture media of primary articular chondrocytes increased the proliferation of these cells and increased their production of extracellular matrix. To assess the receptor selectivity of FGF18, BaF3 cells stably expressing the genes for the major splice variants of Fgfr1-3 were used. Proliferation of cells expressing Fgfr 3-(IIIc) or Fgfr 2-(IIIc) was increased by incubation with FGF18. Using FGFR-Fc fusion proteins and BaF3 cells expressing Fgfr 3-(IIIc), only FGFR 3-(IIIc)-Fc, FGFR 2-(IIIc)-Fc or FGFR 4-Fc reduced FGF18-mediated cell proliferation. Expression of Fgf18, Fgfr 3-(IIIc) and Fgfr 2-(IIIc) mRNAs was localized to chondrocytes of human articular cartilage by in situ hybridization. CONCLUSION: These data demonstrate that Fgf18 can act as a trophic factor for elastic chondrocytes and their progenitors in vivo and articular chondrocytes cultured in vitro. Expression of Fgf18 and the genes for two of its receptors in chondrocytes suggests that Fgf18 may play an autocrine role in the biology of normal articular cartilage.


Asunto(s)
Condrocitos/metabolismo , Factores de Crecimiento de Fibroblastos/genética , Adulto , Animales , Cartílago Articular/química , División Celular/efectos de los fármacos , Movimiento Celular/efectos de los fármacos , Condrocitos/citología , Colágeno Tipo II/metabolismo , Oído Externo , Femenino , Factores de Crecimiento de Fibroblastos/análisis , Expresión Génica , Técnicas de Transferencia de Gen , Humanos , Inmunohistoquímica/métodos , Hibridación in Situ/métodos , Ratones , Ratones Desnudos , Proteoglicanos/metabolismo , ARN Mensajero/análisis , Receptores de Factores de Crecimiento de Fibroblastos/análisis , Receptores de Factores de Crecimiento de Fibroblastos/genética , Proteínas Recombinantes/farmacología , Porcinos
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