Micromotions at the Bone Implant Interface Up-Regulate Osteoblasts-Mediated Activation of Osteoclasts in Ex Vivo Human Samples

2007 ◽  
Author(s):  
Vincent A. Stadelmann ◽  
Dominique P. Pioletti
Keyword(s):  
Aseptic Loosening ◽  
Ex Vivo ◽  
Fibrous Tissue ◽  
Joint Prosthesis ◽  
Implant Fixation ◽  
Bone Implant ◽  
Common Cause ◽  
Progressive Deterioration ◽  
Cemented Implants ◽  
Fibrous Tissues

A radiolucent zone at the interface of bone and implants in total joint prosthesis is frequently observed in uncemented and cemented implants. This radiolucent zone, representing a fibrous tissue, is the result of the progressive deterioration of the bone surrounding implants. Fibrous tissues affect the implant fixation, increasing then the risk of aseptic loosening. Today, aseptic loosening is the most common cause of arthroplasties revisions.

Long-term competing risks for overall and cause-specific failure of rotating-hinge distal femoral arthroplasty for tumour reconstruction

2021 ◽  
Vol 103-B (8) ◽  
pp. 1405-1413
Author(s):  
Koichi Ogura ◽  
Tomohiro Fujiwara ◽  
Carol D. Morris ◽  
Patrick J. Boland ◽  
John H. Healey
Keyword(s):  
Aseptic Loosening ◽  
Femoral Component ◽  
Distal Femur ◽  
Quadriceps Muscle ◽  
Competing Risk ◽  
Implant Fixation ◽  
Bone Implant ◽  
Rotating Hinge ◽  
Rotating Hinge Knee

Aims Rotating-hinge knee prostheses are commonly used to reconstruct the distal femur after resection of a tumour, despite the projected long-term burden of reoperation due to complications. Few studies have examined the factors that influence their failure and none, to our knowledge, have used competing risk models to do so. The purpose of this study was to determine the risk factors for failure of a rotating-hinge knee distal femoral arthroplasty using the Fine-Gray competing risk model. Methods We retrospectively reviewed 209 consecutive patients who, between 1991 and 2016, had undergone resection of the distal femur for tumour and reconstruction using a rotating-hinge knee prosthesis. The study endpoint was failure of the prosthesis, defined as removal of the femoral component, the tibial component, or the bone-implant fixation; major revision (exchange of the femoral component, tibial component, or the bone-implant fixation); or amputation. Results Multivariate Fine-Gray regression analyses revealed different hazards for each Henderson failure mode: percentage of femoral resection (p = 0.001) and extent of quadriceps muscle resection (p = 0.005) for overall prosthetic failure; extent of quadriceps muscle resection (p = 0.002) and fixation of femoral component (p = 0.011) for type 2 failure (aseptic loosening); age (p = 0.009) and percentage of femoral resection (p = 0.019) for type 3 failure (mechanical failure); and type of joint resection (p = 0.037) for type 4 (infection) were independent predictors. A bone stem ratio of > 2.5 reliably predicted aseptic loosening. Conclusion We identified independent risk factors for overall and cause-specific prosthetic failure after rotating-hinge knee distal femoral arthroplasty using a competing risk Fine-Gray model. A bone stem ratio > 2.5 reliably predicts aseptic loosening. An accurate knowledge of the risks of distal femoral arthroplasty after resection for tumour assists surgical planning and managing patient expectations. Cite this article: Bone Joint J 2021;103-B(8):1405–1413.

scholarly journals Vascularised bone graft is an effective technique for extracortical bone bridging to combat cemented megaprosthesis loosening at the bone–implant junction

2020 ◽  
Vol 28 (3) ◽  
pp. 230949902095816 ◽  
Author(s):  
Michelle Hilda Luk ◽  
Andy Hon-Fai Yee ◽  
Raymond Yau ◽  
Kenneth Wai-Yip Ho ◽  
Ying-Lee Lam
Keyword(s):  
Bone Graft ◽  
Aseptic Loosening ◽  
Bone Growth ◽  
Implant Loosening ◽  
Implant Fixation ◽  
Bone Implant ◽  
Radiological Score ◽  
Vascularised Bone Graft ◽  
Without Bone Graft

Introduction: The bone–implant junction is a potential site for aseptic loosening. Extracortical bone bridging at the bone–implant junction is advocated to improve implant fixation by forming a biological seal. We propose a novel technique with vascularised bone graft (VBG) to form an extracortical bone bridge at the bone–implant junction to enhance implant stability. We compared the clinical and radiological outcomes for tumour megaprostheses performed (1) with and without bone graft and (2) with non-vascularised versus VBG technique. Methods: Forty-six tumour megaprosthesis procedures from 1 June 2007 to 31 October 2017 were identified from hospital records. Twenty-eight operations incorporated bone graft at the bone–implant junction, and 18 did not. Of these 28 bone graft procedures, 13 involved VBG, and 15 did not (non-VBG). The VBG technique involves resecting a short segment of healthy bone beyond the oncological margin with its preserved blood supply, splitting it, then securing it over the junction. Clinical outcomes assessed included loosening, fracture and recurrence. Extracortical bone growth at the bone–implant junction was quantified radiologically at intervals 0–24 months post-operatively. The mean follow-up was 4.27 years. Results: There were five incidences (27.8%) of loosening in the non-bone graft group compared to zero in the bone graft group ( p = 0.03). There was a higher radiological score of extracortical bone growth in the bone graft group compared to no bone graft at 3–24 months post-operatively ( p < 0.05). Within the bone graft group, the VBG group fared superior at 6 and 12 months post-operatively compared to non-VBG ( p < 0.05), as well as a lower rate of radiological junctional resorption ( p = 0.04). Conclusions: We recommend bone grafting for its merits of less implant loosening. We propose the VBG technique to combat early aseptic loosening in megaprosthesis replacement as there was a higher radiological score compared to non-VBG.

scholarly journals MiR-140-3p inhibits the cell viability and promotes apoptosis of synovial fibroblasts in rheumatoid arthritis through targeting sirtuin 3

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Beibei Zu ◽  
Lin Liu ◽  
Jingya Wang ◽  
Meirong Li ◽  
Junxia Yang
Keyword(s):  
Rheumatoid Arthritis ◽  
Cell Viability ◽  
Cell Apoptosis ◽  
Caspase 3 ◽  
Pearson Correlation ◽  
Fibrous Tissue ◽  
Synovial Fibroblasts ◽  
Cell Counting ◽  
Sirtuin 3 ◽  
Fibrous Tissues

Abstract Background Synovial fibroblasts (SFs) with the abnormal expressions of miRNAs are the key regulator in rheumatoid arthritis (RA). Low-expressed miR-140-3p was found in RA tissues. Therefore, we attempted to investigate the effect of miR-140-3p on SFs of RA. Methods RA and normal synovial fibrous tissue were gathered. The targets of miR-140-3p were found by bioinformatics and luciferase analysis. Correlation between the expressions of miR-140-3p with sirtuin 3 (SIRT3) was analyzed by Pearson correlation analysis. After transfection, cell viability and apoptosis were detected by cell counting kit-8 and flow cytometry. The expressions of miR-140-3p, SIRT3, Ki67, Bcl-2, Bax, and cleaved Caspase-3 were detected by RT-qPCR or western blot. Results Low expression of miR-140-3p and high expression of SIRT3 were found in RA synovial fibrous tissues. SIRT3 was a target of miR-140-3p. SIRT3 expression was negatively correlated to the expression of miR-140-3p. MiR-140-3p mimic inhibited the MH7A cell viability and the expressions of SIRT3, Ki67, and Bcl-2 and promoted the cell apoptosis and the expressions of Bax and cleaved Caspase-3; miR-140-3p inhibitor showed an opposite effect to miR-140-3p mimic on MH7A cells. SIRT3 overexpression not only promoted the cell viability and inhibited cell apoptosis of MH7A cells but also reversed the effect of miR-140-3p mimic had on MH7A cells. Conclusions The results in this study revealed that miR-140-3p could inhibit cell viability and promote apoptosis of SFs in RA through targeting SIRT3.

scholarly journals Comparison of the Resistance to Bending Forces of the 4.5 LCP Plate-rod Construct and of 4.5 LCP Alone Applied to Segmental Femoral Defects in Miniature Pigs

2010 ◽  
Vol 79 (4) ◽  
pp. 613-620 ◽  
Author(s):  
Lucie Urbanová ◽  
Robert Srnec ◽  
Pavel Proks ◽  
Ladislav Stehlík ◽  
Zdeněk Florian ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Femoral Diaphysis ◽  
Miniature Pig ◽  
Femoral Bone ◽  
Bone Implant ◽  
Miniature Pigs ◽  
Bone Defect Healing ◽  
Considerable Strain

The study deals with the determination of mechanical properties, namely resistance to bending forces, of flexible buttress osteosynthesis using two different bone-implant constructs stabilizing experimental segmental femoral bone defects (segmental ostectomy) in a miniature pig ex vivo model using 4.5 mm titanium LCP and a 3 mm intramedullary pin (“plate and rod” construct) (PR-LCP), versus the 4.5 mm titanium LCP alone (A-LCP). The “plate and rod” fixation (PR-LCP) of the segmental femoral defect is significantly more resistant (p < 0.05) to bending forces (200 N, 300 N, and 500 N) than LCP alone (A-LCP). Stabilisation of experimental segmental lesions of the femoral diaphysis in miniature pigs by flexible bridging osteosynthesis 4.5 mm LCP in combination with the “plate and rod” construct appears to be a suitable fixation of non-reducible fractures where considerable strain of the implants by bending forces can be assumed. These findings will be used in upcoming in vivo experiments in the miniature pig to investigate bone defect healing after transplantation of mesenchymal stem cells in combination with biocompatible scaffolds.

scholarly journals Finite-element analysis of the influence of tibial implant fixation design of total ankle replacement on bone–implant interfacial biomechanical performance

2020 ◽  
Vol 28 (3) ◽  
pp. 230949902096612
Author(s):  
Jian Yu ◽  
Chao Zhang ◽  
Wen-Ming Chen ◽  
Dahang Zhao ◽  
Pengfei chu ◽  
...  
Keyword(s):  
Finite Element ◽  
Total Ankle Replacement ◽  
Implant Design ◽  
Fixation Method ◽  
Implant Loosening ◽  
Implant Fixation ◽  
Bone Resection ◽  
Bone Implant ◽  
Initial Stability ◽  
Ankle Replacement

Purpose: Implant loosening in tibia after primary total ankle replacement (TAR) is one of the common postoperative problems in TAR. Innovations in implant structure design may ideally reduce micromotion at the bone–implant interface and enhance the bone-implant fixation and initial stability, thus eventually prevents long-term implant loosening. This study aimed to investigate (1) biomechanical characteristics at the bone–implant interface and (2) the influence of design features, such as radius, height, and length. Methods: A total of 101 finite-element models were created based on four commercially available implants. The models predicted micromotion at the bone–implant interface, and we investigated the impact of structural parameters, such as radius, length, and height. Results: Our results suggested that stem-type implants generally required the highest volume of bone resection before implantation, while peg-type implants required the lowest. Compared with central fixation features (stem and keel), peripherally distributed geometries (bar and peg) were associated with lower initial micromotions. The initial stability of all types of implant design can be optimized by decreasing fixation size, such as reducing the radius of the bars and pegs and lowering the height. Conclusion: Peg-type tibial implant design may be a promising fixation method, which is required with a minimum bone resection volume and yielded minimum micromotion under an extreme axial loading scenario. Present models can serve as a useful platform to build upon to help physicians or engineers when making incremental improvements related to implant design.

scholarly journals Mechanical flexural ex vivo study of osteotomized swine femurs stabilized with two types of polyamide 12 rods

2017 ◽  
Vol 47 (8) ◽  
Author(s):  
Juliana Scarpa da Silveira Almeida ◽  
Débora de Oliveira Garcia ◽  
Renato Camargo Bortholin ◽  
Carlos Amaral Razzino ◽  
Cristiane dos Santos Honsho ◽  
...  
Keyword(s):  
Bone Fractures ◽  
Ex Vivo ◽  
Polymeric Materials ◽  
Fracture Site ◽  
Medullary Canal ◽  
Modulus Of Rupture ◽  
Long Bone ◽  
Bone Implant ◽  
Polyamide 12 ◽  
Implant System

ABSTRACT: Long bone fractures are commonly in surgery routine and several bone imobilization techniques are currently available. Technological progress has enabled to use low cost materials in surgical procedures. Thus, the aim of this study was to evaluate the applicability of polyamide 12 rods, solid and hollow in swine femurs, comparing them through flexion strength. This study had as second aim to fix the locking errors, commom place in interlocking nails, once polyamide 12 allows perforation in any direction by orthopaedic screw. Six groups were used: G1 - eight whole swine femurs; G2 - eight whole swine femurs with drilled medullary canal; G3 - two solid polyamide 12 rods; G4 - two hollow polyamide 12 rods; G5 - eight osteotomized drilled swine femurs with a solid polyamide 12 rod implanted in the medullary canal and locked by four 316L stainless steel screws; and G6 - similar to G5 but using hollow rods instead of solid ones. No significant differences were observed for the modulus of rupture between solid and hollow rods, demonstrating that both rods had similar performances. These results led to the speculation that the addition of other polymers to the hollow rods could increase their strength and thus the bone-implant system. Furthermore, the comparison between G1, G5 and G6 could be analyzed using the finite element method in future. New polymeric materials may be developed based on the data from this study, strengthening the bone-implant system and making possible screws to be placed in any direction, nullifying the detrimental forces on the fracture site.

scholarly journals Biomechanics in dental implants

2021 ◽  
Vol 7 (3) ◽  
pp. 131-136
Author(s):  
Poonam Prakash ◽  
Ambika Narayanan
Keyword(s):  
Dental Implants ◽  
Fibrous Tissue ◽  
Primary Stability ◽  
Biological Tissues ◽  
Implant Design ◽  
Implant Fixation ◽  
Implant Surface ◽  
Bone Apposition ◽  
Functional Connection ◽  
Secondary Stage

Achieving primary stability in dental implants is crucial factor for accomplishing successful osteointegration with bone. Micro-motions higher than the threshold of 50 to 100 μm can lead to formation of fibrous tissue at the bone-to-implant interface. Therefore, osteointegration may be vitiated due to insufficient primary stability. Osseointegration is defined as a direct and functional connection between the implant biomaterial and the surrounding bone tissue. Osseointegration development requires an initial rigid implant fixation into the bone at the time of surgery and a secondary stage of new bone apposition directly onto the implant surface. Dental implants function to transfer the load to the surrounding biological tissues. Due to the absence of a periodontal ligament, its firm anchorage to bone, various forces acting on it and the presence of prosthetic components, they share a complex biomechanical relationship. The longevity of these osseointegrated implants depend on optimizing these complex interactions. Hence, the knowledge of forces acting on implant, design considerations of implant and bone mechanics is essential to fabricate an optimized implant supported prosthesis.

Osteoconductivity of bioactive Ti-6Al-4V implants with lattice-shaped interconnected large pores fabricated by electron beam melting

2020 ◽  
pp. 088532822096821
Author(s):  
Mikinobu Goto ◽  
Akihiko Matsumine ◽  
Seiji Yamaguchi ◽  
Hiroyuki Takahashi ◽  
Koji Akeda ◽  
...  
Keyword(s):  
Electron Beam ◽  
Metal Powder ◽  
Metal Surface ◽  
Electron Beam Melting ◽  
Fibrous Tissue ◽  
Apatite Formation ◽  
Implant Fixation ◽  
Push Out ◽  
Interconnected Pores

Additive manufacturing has facilitated the fabrication of orthopedic metal implants with interconnected pores. Recent reports have indicated that a pore size of 600 μm is beneficial for material-induced osteogenesis. However, the complete removal of the metal powder from such small pores of implants is extremely difficult especially in electron beam melting (EBM). We therefore developed a new type of Ti-6Al-4V implant with lattice-shaped interconnected pores measuring 880–1400 μm, which allowed for the easy removal of metal powder. This implant was fabricated by EBM and treated with NaOH, CaCl2, heat, and water (ACaHW treatment) to render the metal surface bioactivity. In the present study, the mechanical and chemical property of the implants and the biocompatibility were evaluated. The SEM and micro-CT images demonstrated the 3D interconnectivity of the porous structures. The average porosity of the porous titanium implant was 57.5%. The implant showed maximum compressive load of 78.9 MPa and Young's modulus of 3.57 GPa which matches that of human cortical bone. ACaHW treatment of the porous Ti-6Al-4V implants induced apatite formation in simulated body fluid in vitro. The ACaHW-treated porous implants harvested from rabbit femoral bone showed direct bonding of bone to the metal surface without interposition of fibrous tissue. The porous ACaHW-treated implant had a higher affinity to the bone than the untreated one. The mechanical strength of implant fixation assessed using the push-out test was significantly higher in the ACaHW-treated implant than in untreated one. FE-SEM analysis and EDX mapping after push-out test of solid implants showed a lot of bone tissue patches on the surface of the ACaHW-treated implant. These results suggest that the new ACaHW-treated Ti-6Al-4V implant with lattice-shaped interconnected pores is a superior alternative to conventional materials for medical application.

scholarly journals Continuum theory of fibrous tissue damage mechanics using bond kinetics: application to cartilage tissue engineering

2016 ◽  
Vol 6 (1) ◽  
pp. 20150063 ◽  
Author(s):  
Robert J. Nims ◽  
Krista M. Durney ◽  
Alexander D. Cigan ◽  
Antoine Dusséaux ◽  
Clark T. Hung ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Damage Mechanics ◽  
Multiple Bond ◽  
Fibrous Tissue ◽  
Cartilage Tissue Engineering ◽  
Cartilage Tissue ◽  
State Variables ◽  
Distribution Models ◽  
Observable State ◽  
Fibrous Tissues

This study presents a damage mechanics framework that employs observable state variables to describe damage in isotropic or anisotropic fibrous tissues. In this mixture theory framework, damage is tracked by the mass fraction of bonds that have broken. Anisotropic damage is subsumed in the assumption that multiple bond species may coexist in a material, each having its own damage behaviour. This approach recovers the classical damage mechanics formulation for isotropic materials, but does not appeal to a tensorial damage measure for anisotropic materials. In contrast with the classical approach, the use of observable state variables for damage allows direct comparison of model predictions to experimental damage measures, such as biochemical assays or Raman spectroscopy. Investigations of damage in discrete fibre distributions demonstrate that the resilience to damage increases with the number of fibre bundles; idealizing fibrous tissues using continuous fibre distribution models precludes the modelling of damage. This damage framework was used to test and validate the hypothesis that growth of cartilage constructs can lead to damage of the synthesized collagen matrix due to excessive swelling caused by synthesized glycosaminoglycans. Therefore, alternative strategies must be implemented in tissue engineering studies to prevent collagen damage during the growth process.

The Effect of Sintering Temperature to the Quality of Hydroxyapatite Coating on Cobalt Alloys as the Candidate of Bone Implant Prosthesis

2017 ◽  
Vol 32 ◽  
pp. 59-68 ◽  
Author(s):  
Aminatun ◽  
Dyah Hikmawati ◽  
M. Yasin
Keyword(s):  
Aseptic Loosening ◽  
Hip Replacement ◽  
Sintering Temperature ◽  
Thick Layer ◽  
Sintering Process ◽  
Bone Implant ◽  
Ha Coating ◽  
Coating Method ◽  
Implant Prosthesis

Total hip replacement (THR) that is widely used today is the cemented type, which its application will lead to aseptic loosening. To avoid the occurrence of aseptic loosening, THR coated with hydroxyapatite (HA) is required because HA is osteoconductive which can stimulate the growth of osteoblasts. This study aims to determine the optimum sinter temperature which produce HA coating suitable as implant material. To achieve these objectives, the electrophoretic deposition (EPD) conducted coating method at concentrations of HA 1,0M, voltage of 100V for 30 minutes and then sintered at temperatures are 550°C, 700°C and 900°C respectively detention for 10 minutes. The results showed that the treatment of sintering after the coating process through the EPD method affect the characteristics of the layer thus formed. Sintering process affects the crystallinity of the HA layer. The higher the sintering temperature the higher its crystallinity. The higher the crystallinity the stronger the HA layer attached to the substrate cobalt alloy. Based on this research, the selected sintering temperature was 900 °C for 10 minutes which produced a layer of HA with the best characteristics that meet the standard of implant prosthesis, the crystallinity of 89.4%, thick layer of 70.80 ± 4.18 μm, adhesion strength of 21.87 ± 0.23 MPa, the corrosion rate of 0.025 mpy and 70.3% cell viability.

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