PERIPROSTHETIC BONE DENSITY CHANGES EVALUATION USING COMPUTED TOMOGRAPHY

Background: Due to aging, tissue regeneration gradually declines. Contemporary strategies to promote tissue-specific regeneration, in particular in elderly patients, often include synthetic material apt for implantation primarily aiming at upholding body functions and regaining appropriate anatomical and functional integrity. Objective: Biomaterials suitable for complex reconstruction surgical procedures have to exert high physicochemical stability and biocompatibility. Method: A polymer made of poly-L-lactic acid and poly-ε-caprolactone was synthesized by means of a novel tin-free catalytic process. The material was tested in a bioreactor-assisted perfusion culture and implanted in a sheep model for lateral augmentation of the mandible. Histological and volumetric evaluation was performed 3 and 6 months post-implantation. Results: After synthesis the material could be further refined by cryogrinding and sintering, thus yielding differently porous scaffolds that exhibited a firm and stable appearance. In perfusion culture, no disintegration was observed for extended periods of up to 7 weeks, while mesenchymal stromal cells readily attached to the material, steadily proliferated, and deposited extracellular calcium. The material was tested in vivo together with autologous bone marrow-derived stromal cells. Up to 6 months post-implantation, the material hardly changed in shape with composition also refraining from foreign body reactions. Conclusion: Given the long-term shape stability in vivo, featuring imperceptible degradation and little scarring as well as exerting good compatibility to cells and surrounding tissues, this novel biomaterial is suitable as a space filler in large anatomical defects.

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Immediate Changes of Bone Density Caused by the Implantation of a Femoral Stem - A Dexa Study

Hip International ◽

10.5301/hip.2011.8841 ◽

2011 ◽

Vol 21 (6) ◽

pp. 706-712 ◽

Cited By ~ 3

Author(s):

Ulf G. Leichtle ◽

Jeremi Leasure ◽

Franz Martini ◽

Carmen I. Leichtle

Keyword(s):

Bone Density ◽

Bone Loss ◽

Femoral Stem ◽

Periprosthetic Bone ◽

Experimental Conditions ◽

Press Fit ◽

Custom Made ◽

Femoral Stems ◽

Cementless Prosthesis ◽

Post Implantation

Considerable immediate periprosthetic bone density changes after implantation of femoral stems have been observed comparing DEXA measurements taken pre- and post-operatively. This is important in relation to the interpretation of DEXA studies. We analysed these density changes under standardised experimental conditions. Five human femora were implanted with a custom made femoral stem and ten femora with a standard cementless prosthesis. Densitometry was performed at various stages of implantation. Following rasping only slight density changes were noted (–2.7% to +0.7%). Comparing post-implantation and pre-operative measurements, all custom made stems with a proximal press-fit demonstrated clear increases in proximal periprosthetic bone density of +11% and +14%. In contrast, the standard prosthesis with a distal press-fit showed a loss of –5% and –2% in the proximal zones. Measurements following removal of the implants demonstrated hardly any density changes (0% to –4%) compared to the pre-operative measurements. We concluded that compacting of trabecular bone or bone loss due to rasping are not the main causes of density changes. Substantial measuring errors exist. For examination of periprosthetic bone density changes, pre-operative initial measurements should not be used as a baseline for comparison. Studies should commence with an immediate postoperative measurement.

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EXPLORING CORTICAL BONE DENSITY THROUGH THE ULTRASOUND INTEGRATED REFLECTION COEFFICIENT

Acta Ortopédica Brasileira ◽

10.1590/1413-785220182604177202 ◽

2018 ◽

Vol 26 (4) ◽

pp. 255-259

Author(s):

Daniel Patterson Matusin ◽

Aldo José Fontes-Pereira ◽

Paulo Tadeu Cardozo Ribeiro Rosa ◽

Thiago Barboza ◽

Sergio Augusto Lopes de Souza ◽

...

Keyword(s):

Computed Tomography ◽

Bone Density ◽

Reflection Coefficient ◽

Cortical Bone ◽

Quantitative Computed Tomography ◽

Density Variation ◽

Bone Surface ◽

Weak Correlation ◽

Level Of Evidence ◽

The Relationship

ABSTRACT Objective: This work evaluates the relationship between ultrasonic reflection and bone density from fourteen cylindrical bovine cortical bone samples (3.0-cm thick). Methods: Twenty US reflection signals per sample were acquired along the bone surface (2.0-mm step). The Integrated Reflection Coefficient (IRC) from each signal was compared to Quantitative Computed Tomography (QCT). Results: Seven IRC and QCT curves presented Pearson's Correlation R-values above 0.5. For weak correlation curves, QCT and IRC showed similar trends in several segments. Conclusion: IRC was sensitive to bone density variation. Level of Evidence: Experimental Study, Investigating a Diagnostic Test.

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Predicting Bone Remodeling in Response to Orthopedic Implantations: Computational Study Using a Mechano-Biochemical Model

10.32920/ryerson.14653821 ◽

2021 ◽

Author(s):

Pouria Tavakkoli Avval

Keyword(s):

Bone Density ◽

Bone Loss ◽

Bone Remodeling ◽

Bone Fracture ◽

Mineral Density ◽

Periprosthetic Bone ◽

Premature Failure ◽

Gruen Zone ◽

Periprosthetic Bone Loss

Periprosthetic bone loss following orthopedic implantations is a serious concern leading to the premature failure of the implants. Therefore, investigating bone remodeling in response to orthopedic implantations is of paramount importance for the purpose of designing long lasting prostheses. In this study, a predictive bone remodeling model (Thermodynamic-based model) was employed to simulate the long-term response of femoral density to total hip arthroplasty (THA), bone fracture plating and intramedullary (IM) nailing. The ability of the model in considering the coupling effect between mechanical loading and bone biochemistry is its unique characteristic. This research provided quantitative data for monitoring bone density changes throughout the femoral bone. The results obtained by the thermodynamic-based model agreed well with the bone morphology and the literature. The study revealed that the most significant periprosthetic bone loss in response to THA occurred in calcar region (Gruen zone 7). Conversely, the region beneath the hip stem (Gruen zone 4) experienced the lowest bone mineral density (BMD) changes. It was found that the composite hip implant and IM nail were more advantageous over the metallic ones as they induced less stress shielding and provided more uniform bone density changes following the surgery. The research study also showed that, due to plating, the areas beneath the bone fracture plate experienced severe bone loss. However, some level of bone formation was observed at the vicinity of the most proximal and distal screw holes in both lateral and anterior plated femurs. Furthermore, in terms of long-term density distributions, the anterior plating was not superior to the lateral plating.

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Long-term results of the custom- made hip endoprostheses Evolution K® and Adaptiva®: A prospective cohort study

Orthopedic Reviews ◽

10.4081/or.2021.9014 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Steffen Axt ◽

Andreas Kirschniak ◽

Lena Axt ◽

Manuel Braun ◽

Christian Beltzer ◽

...

Keyword(s):

Survival Rate ◽

Bone Density ◽

Stress Shielding ◽

Clinical Results ◽

Long Term Results ◽

Harris Hip Score ◽

Periprosthetic Bone ◽

Hip Prostheses ◽

Custom Made

The aim of our study is to evaluate clinical long-term results and determine changes in periprosthetic bone density of the custom-made hip prostheses Evolution-K® and Adaptiva®. Periprosthetic bone density were evaluated by means of DEXA (LunariDXA- Prodigy® bone densitometer) with a long-term follow-up of 16 (15-18) years (Evolution-K®) in 24 patients and 13 (13-15) years (Adaptiva®) in 41 patients. Evolution- K® had a survival rate of 92% and yielded 79/100 points in Harris Hip Score, a mediocre result. Adaptiva® had a survival rate of 99% and achieved a good score of 88/100 points. Bone density measurements demonstrated the greatest loss of bone density in the proximal regions of interest (ROI) for both prosthesis types (Evolution-K®: -25.8% ROI 1, -40.3% ROI 7; -8.3% ROI 2, -10.4% ROI 6; Adaptiva®: -29.8% ROI 7, -6.8% ROI 6, +14.3% ROI 3, +3.1% ROI 4). Adaptiva® yielded a good clinical result as compared to Evolution-K® with only average clinical results. Both prostheses clearly showed signs of “stress shielding”. Here, the Adaptiva® achieved reduced bone density loss as compared to the Evolution-K®.

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Implants delivering bisphosphonate locally increase periprosthetic bone density in an osteoporotic sheep model. A pilot study

10.22203/ecm.v016a02 ◽

2008 ◽

Vol 16 ◽

pp. 10-16 ◽

Cited By ~ 71

Author(s):

VA Stadelmann ◽

◽

O Gauthier ◽

A Terrier ◽

J-M Bouler ◽

...

Keyword(s):

Pilot Study ◽

Bone Density ◽

Periprosthetic Bone ◽

Sheep Model

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Predicting Bone Remodeling in Response to Orthopedic Implantations: Computational Study Using a Mechano-Biochemical Model

10.32920/ryerson.14653821.v1 ◽

2021 ◽

Author(s):

Pouria Tavakkoli Avval

Keyword(s):

Bone Density ◽

Bone Loss ◽

Bone Remodeling ◽

Bone Fracture ◽

Mineral Density ◽

Periprosthetic Bone ◽

Premature Failure ◽

Gruen Zone ◽

Periprosthetic Bone Loss

Periprosthetic bone loss following orthopedic implantations is a serious concern leading to the premature failure of the implants. Therefore, investigating bone remodeling in response to orthopedic implantations is of paramount importance for the purpose of designing long lasting prostheses. In this study, a predictive bone remodeling model (Thermodynamic-based model) was employed to simulate the long-term response of femoral density to total hip arthroplasty (THA), bone fracture plating and intramedullary (IM) nailing. The ability of the model in considering the coupling effect between mechanical loading and bone biochemistry is its unique characteristic. This research provided quantitative data for monitoring bone density changes throughout the femoral bone. The results obtained by the thermodynamic-based model agreed well with the bone morphology and the literature. The study revealed that the most significant periprosthetic bone loss in response to THA occurred in calcar region (Gruen zone 7). Conversely, the region beneath the hip stem (Gruen zone 4) experienced the lowest bone mineral density (BMD) changes. It was found that the composite hip implant and IM nail were more advantageous over the metallic ones as they induced less stress shielding and provided more uniform bone density changes following the surgery. The research study also showed that, due to plating, the areas beneath the bone fracture plate experienced severe bone loss. However, some level of bone formation was observed at the vicinity of the most proximal and distal screw holes in both lateral and anterior plated femurs. Furthermore, in terms of long-term density distributions, the anterior plating was not superior to the lateral plating.

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Attachment of oral bacteria to titanium surfaces: An SEM study

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100170074 ◽

1994 ◽

Vol 52 ◽

pp. 468-469

Author(s):

J. E. Laffoon ◽

R. L. Anderson ◽

J. C. Keller ◽

C. D. Wu-Yuan

Keyword(s):

Technical Problem ◽

Titanium Implant ◽

Oral Bacteria ◽

Bacterial Cells ◽

Thin Sections ◽

Surface Ultrastructure ◽

Sem Study ◽

Key Factor ◽

Titanium Surfaces

Titanium (Ti) dental implants have been used widely for many years. Long term implant failures are related, in part, to the development of peri-implantitis frequently associated with bacteria. Bacterial adherence and colonization have been considered a key factor in the pathogenesis of many biomaterial based infections. Without the initial attachment of oral bacteria to Ti-implant surfaces, subsequent polymicrobial accumulation and colonization leading to peri-implant disease cannot occur. The overall goal of this study is to examine the implant-oral bacterial interfaces and gain a greater understanding of their attachment characteristics and mechanisms. Since the detailed cell surface ultrastructure involved in attachment is only discernible at the electron microscopy level, the study is complicated by the technical problem of obtaining titanium implant and attached bacterial cells in the same ultra-thin sections. In this study, a technique was developed to facilitate the study of Ti implant-bacteria interface.Discs of polymerized Spurr’s resin (12 mm x 5 mm) were formed to a thickness of approximately 3 mm using an EM block holder (Fig. 1). Titanium was then deposited by vacuum deposition to a film thickness of 300Å (Fig. 2).

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