Wyniki wyszukiwania - Biblioteka Nauki

1

The Influence of Mechanical, and Material Factors on the Biological Adaptation Processes of the Femoral Bone Implants

100%

Jasik A. , Mroczek M.

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tom Vol. 61, iss. 1

189--194

EN

The study covers some aspects of the issue of determination of mutual connections between the mechanical and material factors, as well the biological implant adaptation processes. The main objective of the operation was adopted to develop models of cementless hip prosthesis company Fitmore Zimmer, taking into account the heterogeneity of material properties of bone tissue. These models were loaded in particular stages of the human gate and then they were used for the analysis of stress changes. The identification of the relations between the mechanical properties of osseous tissue required the conducting of computer simulations by means of the Finite Element Method (FEM).

2

NiTi shape memory clamps for bone fracture treatment in rabbit: preliminary report

100%

Goryczka T. , Lekston Z. , Lelątko J. , Szponder T. , Paluch J.

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tom Vol. 19, no. 138 spec. iss.

72

3

Allergy to orthopedic metal implants - A prospective study

100%

Kręcisz B. , Kieć-Świerczyńska M. , Chomiczewska-Skóra D.

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nr 4

463-469

EN

Objectives: Evaluation of the allergenic properties of the metal knee or hip joint implants 24 months post surgery and assessment of the relation between allergy to metals and metal implants failure. Materials and Methods: The study was conducted in two stages. Stage I (pre-implantation) - 60 patients scheduled for arthroplasty surgery. Personal interview, dermatological examination and patch testing with 0.5% potassium dichromate, 1.0% cobalt chloride, 5.0% nickel sulfate, 2.0% copper sulfate, 2.0% palladium chloride, 100% aluminum, 1% vanadium chloride, 5% vanadium, 10% titanium oxide, 5% molybdenum and 1% ammonium molybdate tetrahydrate were performed. Stage II (post-surgery) - 48 subjects participated in the same procedures as those conducted in Stage I. Results: Stage I - symptoms of "metal dermatitis" were found in 21.7% of the subjects: 27.9% of the females, 5.9% of the males. Positive patch test results were found in 21.7% of the participants, namely to: nickel (20.0%); palladium (13.3%); cobalt (10.0%); and chromium (5.9%). The allergy to metals was confi rmed by patch testing in 84.6% of the subjects with a history of metal dermatitis. Stage II - 10.4% of the participants complained about implant intolerance, 4.2% of the examined persons reported skin lesions. Contact allergy to metals was found in 25.0% of the patients: nickel 20.8%, palladium 10.4%, cobalt 16.7%, chromium 8.3%, vanadium 2.1% Positive post-surgery patch tests results were observed in 10.4% of the patients. The statistical analysis of the pre- and post-surgery patch tests results showed that chromium and cobalt can be allergenic in implants. Conclusions: Metal orthopedic implants may be the primary cause of allergies. that may lead to implant failure. Patch tests screening should be obligatory prior to providing implants to patients reporting symptoms of metal dermatitis. People with confi rmed allergies to metals should be provided with implants free from allergenic metals.

4

The carbon layers for bio-tribological applications

63%

Zdravecka E. , Franta L. , Ondac M.

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tom z. 81 [277]

151-154

EN

One of alternatives for improving the wear resistance and corrosion of biomaterials is the application of protective coatings. DLC coatings are one of the most attractive proposal of the last years for biomedical applications. The aim of this contribution is to compare the mechanical properties for CoCr materials surfaces deposited with DLC coatings under different deposition parameters. DLC coatings were deposited by PVD method (physical vapor deposition) on CrCo alloy-substrate used for bioimplants.

5

Experimental Investigations on the Structural-Osteoinductive Properties of Porous Coatings on Orthopaedic Implants

51%

Uklejewski R. , Winiecki M. , Mielniczuk J. , Auguściński A. , Rogala P.

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tom Vol. 30, No. 4

171-180

EN

The adaptive bone tissue ingrowth into the pore space of a porous coating on orthopaedic implants is influenced by the structural-osteoinductive properties of this coating. The effective bone tissue ingrowth determines the proper fixation of the porous implant in its bony surroundings. The adequate evaluation of the structural-adaptive compatibility of bone-implant interface can be performed on the basis of the two-phase poroelastic biomechanical model of bone tissue and of implant porous coatings with the set of original parameters characterizing the poroaccessibility of implant porous coatings: the effective volumetric porosity φVef, the index of the porous coating space capacity VPM, the effective pore depth ρdef, the representative surface porosity φSrep, the representative pore size ρSrep, the representative angle of the poroaccessibility Ωrep, the index of the enlargement of the adhesive surface of bone-implant interface Ψ, which is proposed in (Mielniczuk et al., 2006; Winiecki et al., 2006; Uklejewski et al., 2005a and 2005b; Winiecki, 2006) to the biostructural evaluation of the porous coated orthopedic implants. This paper presents the results of experimental investigations of the microgeometrical properties of implants porous coatings made with contact profile measurement on the representative examples of endoprostheses stems.

6

The Concept and Geometrical Model of Modern Endoprosthesis Concerning Minimal Invasive Total Hip Resurfacing Arthroplasty (THRA)

51%

Rogala P. , Uklejewski R. , Winiecki M. , Mielniczuk J. , Auguściński A.

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tom Vol. 30, No. 4

89-96

EN

The needle-palisade fixation for total resurfacing arthroplasties of hip and other joints (e.g. knee joint) and the implantation method are presented. The needles are symmetrically spaced on the terminal surfaces of the endoprothesis up to a resistance edge on one portion of the endoprothesis and up to a resistance surface on a second portion of the endoprothesis. The area between multilateral needles will be filled up by new bone formation to the terminal surfaces. The endoprothesis also includes a glenoid cavity and a head which have round terminal surfaces with the multilateral needles placed. The projected multilateral needles have different lengths and mutually parallel axes which are perpendicular to the planes in which the round resistance edge of the glenoid cavity and resistance plane of the head are located. Each of needles is pyramidal. The total surface area of the needle-palisade fixation system is at least seven times greater than total surface area of head external surface and it is when the relation between radius and height of pyramid is about 1 to 5. The implantation method involves the successive introduction of multilateral needles into the spongy bone. The concept of the needle-palisade system for total hip replacement fixation presents: 1) safer operative procedure-press-fit technique, 2) easier revision arthroplasty, 3) good adhesion system (important for example in case of osteoporosis), 4) cortical and cancellous load transmission system, 5) "biological-like" fixation, expectable "life performance" solution, 6) uniform distribution of biomechanical forces. The geometrical model of the new concept of the endoprosthesis for total hip resurfacing arthroplasty created in Autodesk Inventor CAD system is presented. The model is assigned for further experimental researches, i.e.: FEM analysis, virtual simulation of endoprosthesis insertion and the productions of prototypes for biomechanical experiments and pre-clinical investigations.