Pathological assessment of periprosthetic tissues is important, not only for diagnosis, but also for understanding the pathobiology of implant failure. The host response to wear particle deposition in periprosthetic tissues is characterised by cell and tissue injury, and a reparative and inflammatory response in which there is an innate and adaptive immune response to the material components of implant wear. Physical and chemical characteristics of implant wear influence the nature of the response in periprosthetic tissues and account for the development of particular complications that lead to implant failure, such as osteolysis which leads to aseptic loosening, and soft-tissue necrosis/inflammation, which can result in pseudotumour formation. The innate response involves phagocytosis of implant-derived wear particles by macrophages; this is determined by pattern recognition receptors and results in expression of cytokines, chemokines and growth factors promoting inflammation and osteoclastogenesis; phagocytosed particles can also be cytotoxic and cause cell and tissue necrosis. The adaptive immune response to wear debris is characterised by the presence of lymphoid cells and most likely occurs as a result of a cell-mediated hypersensitivity reaction to cell and tissue components altered by interaction with the material components of particulate wear, particularly metal ions released from cobalt-chrome wear particles. Cite this article: Professor N. A. Athanasou. The pathobiology and pathology of aseptic implant failure.
In order to screen the altered gene expression profile in peripheral blood mononuclear cells of patients with osteoporosis, we performed an integrated analysis of the online microarray studies of osteoporosis. We searched the Gene Expression Omnibus (GEO) database for microarray studies of peripheral blood mononuclear cells in patients with osteoporosis. Subsequently, we integrated gene expression data sets from multiple microarray studies to obtain differentially expressed genes (DEGs) between patients with osteoporosis and normal controls. Gene function analysis was performed to uncover the functions of identified DEGs.Objectives
Methods
The ageing population and an increase in both
the incidence and prevalence of cancer pose a healthcare challenge, some
of which is borne by the orthopaedic community in the form of osteoporotic
fractures and metastatic bone disease. In recent years there has
been an increasing understanding of the pathways involved in bone
metabolism relevant to osteoporosis and metastases in bone. Newer
therapies may aid the management of these problems. One group of
drugs, the antibody mediated anti-resorptive therapies (AMARTs)
use antibodies to block bone resorption pathways. This review seeks
to present a synopsis of the guidelines, pharmacology and potential pathophysiology
of AMARTs and other new anti-resorptive drugs. We evaluate the literature relating to AMARTs and new anti-resorptives
with special attention on those approved for use in clinical practice. Denosumab, a monoclonal antibody against Receptor Activator for
Nuclear Factor Kappa-B Ligand. It is the first AMART approved by
the National Institute for Health and Clinical Excellence and the
US Food and Drug Administration. Other novel anti-resorptives awaiting
approval for clinical use include Odanacatib. Denosumab is indicated for the treatment of osteoporosis and
prevention of the complications of bone metastases. Recent evidence
suggests, however, that denosumab may have an adverse event profile
similar to bisphosphonates, including atypical femoral fractures.
It is, therefore, essential that orthopaedic surgeons are conversant
with these medications and their safe usage. Take home message: Denosumab has important orthopaedic indications
and has been shown to significantly reduce patient morbidity in
osteoporosis and metastatic bone disease. Cite this article:
The biomembrane (induced membrane) formed around polymethylmethacrylate (PMMA) spacers has value in clinical applications for bone defect reconstruction. Few studies have evaluated its cellular, molecular or stem cell features. Our objective was to characterise induced membrane morphology, molecular features and osteogenic stem cell characteristics. Following Institutional Review Board approval, biomembrane specimens were obtained from 12 patient surgeries for management of segmental bony defects (mean patient age 40.7 years, standard deviation 14.4). Biomembranes from nine tibias and three femurs were processed for morphologic, molecular or stem cell analyses. Gene expression was determined using the Affymetrix GeneChip Operating Software (GCOS). Molecular analyses compared biomembrane gene expression patterns with a mineralising osteoblast culture, and gene expression in specimens with longer spacer duration (> 12 weeks) with specimens with shorter durations. Statistical analyses used the unpaired student Objectives
Methods
This study aimed to assess the effect of age and osteoporosis on the proliferative and differentiating capacity of bone-marrow-derived mesenchymal stem cells (MSCs) in female rats. We also discuss the role of these factors on expression and migration of cells along the C-X-C chemokine receptor type 4 (CXCR-4) / stromal derived factor 1 (SDF-1) axis. Mesenchymal stem cells were harvested from the femora of young, adult, and osteopenic Wistar rats. Cluster of differentiation (CD) marker and CXCR-4 expression was measured using flow cytometry. Cellular proliferation was measured using Alamar Blue, osteogenic differentiation was measured using alkaline phosphatase expression and alizarin red production, and adipogenic differentiation was measured using Oil red O. Cells were incubated in Boyden chambers to quantify their migration towards SDF-1. Data was analyzed using a Student’s Objectives
Methods
As one of the heat-stable enterotoxins, Rat MSCs were used to test the effects of SEC2 on their proliferation and osteogenic differentiation potentials. A rat femoral fracture model was used to examine the effect of local administration of SEC2 on fracture healing using radiographic analyses, micro-CT analyses, biomechanical testing, and histological analyses.Objectives
Materials and Methods
The purpose of this study was to create a novel The metatarsophalangeal joints of 12 fresh cadaveric bovine feet were skinned and dissected aseptically, and cultured for up to four weeks. Dynamic movement was applied using a custom-made machine on six joints, with the others cultured under static conditions. Chondrocyte viability and matrix glycosaminoglycan (GAG) content were evaluated by the cell viability probes, 5-chloromethylfluorescein diacetate (CMFDA) and propidium iodide (PI), and dimethylmethylene blue (DMMB) assay, respectively.Objectives
Methods
Large bone defects remain a tremendous clinical challenge. There is growing evidence in support of treatment strategies that direct defect repair through an endochondral route, involving a cartilage intermediate. While culture-expanded stem/progenitor cells are being evaluated for this purpose, these cells would compete with endogenous repair cells for limited oxygen and nutrients within ischaemic defects. Alternatively, it may be possible to employ extracellular vesicles (EVs) secreted by culture-expanded cells for overcoming key bottlenecks to endochondral repair, such as defect vascularization, chondrogenesis, and osseous remodelling. While mesenchymal stromal/stem cells are a promising source of therapeutic EVs, other donor cells should also be considered. The efficacy of an EV-based therapeutic will likely depend on the design of companion scaffolds for controlled delivery to specific target cells. Ultimately, the knowledge gained from studies of EVs could one day inform the long-term development of synthetic, engineered nanovesicles. In the meantime, EVs harnessed from
Enhanced micromotions between the implant and surrounding bone can impair osseointegration, resulting in fibrous encapsulation and aseptic loosening of the implant. Since the effect of micromotions on human bone cells is sparsely investigated, an Micromotions ranging from 25 µm to 100 µm were applied as sine or triangle signal with 1 Hz frequency to human osteoblasts seeded on collagen scaffolds. Micromotions were applied for six hours per day over three days. During the micromotions, a static pressure of 527 Pa was exerted on the cells by Ti6Al4V cylinders. Osteoblasts loaded with Ti6Al4V cylinders and unloaded osteoblasts without micromotions served as controls. Subsequently, cell viability, expression of the osteogenic markers collagen type I, alkaline phosphatase, and osteocalcin, as well as gene expression of osteoprotegerin, receptor activator of NF-κB ligand, matrix metalloproteinase-1, and tissue inhibitor of metalloproteinase-1, were investigated.Objectives
Methods
Despite its intrinsic ability to regenerate form and function after injury, bone tissue can be challenged by a multitude of pathological conditions. While innovative approaches have helped to unravel the cascades of bone healing, this knowledge has so far not improved the clinical outcomes of bone defect treatment. Recent findings have allowed us to gain in-depth knowledge about the physiological conditions and biological principles of bone regeneration. Now it is time to transfer the lessons learned from bone healing to the challenging scenarios in defects and employ innovative technologies to enable biomaterial-based strategies for bone defect healing. This review aims to provide an overview on endogenous cascades of bone material formation and how these are transferred to new perspectives in biomaterial-driven approaches in bone regeneration. Cite this article: T. Winkler, F. A. Sass, G. N. Duda, K. Schmidt-Bleek. A review of biomaterials in bone defect healing, remaining shortcomings and future opportunities for bone tissue engineering: The unsolved challenge.
The exact aetiology and pathogenesis of microdamage-induced long bone fractures remain unknown. These fractures are likely to be the result of inadequate bone remodelling in response to damage. This study aims to identify an association of osteocyte apoptosis, the presence of osteocytic osteolysis, and any alterations in sclerostin expression with a fracture of the third metacarpal (Mc-III) bone of Thoroughbred racehorses. A total of 30 Mc-III bones were obtained; ten bones were fractured during racing, ten were from the contralateral limb, and ten were from control horses. Each Mc-III bone was divided into a fracture site, condyle, condylar groove, and sagittal ridge. Microcracks and diffuse microdamage were quantified. Apoptotic osteocytes were measured using TUNEL staining. Cathepsin K, matrix metalloproteinase-13 (MMP-13), HtrA1, and sclerostin expression were analyzed.Objectives
Methods
The mucopolysaccharidoses (MPS) are a group of
inherited lysosomal storage disorders with clinical manifestations relevant
to the orthopaedic surgeon. Our aim was to review the recent advances
in their management and the implications for surgical practice. The current literature about MPSs is summarised, emphasising
orthopaedic complications and their management. Recent advances in the diagnosis and management of MPSs include
the recognition of slowly progressive, late presenting subtypes,
developments in life-prolonging systemic treatment and potentially
new indications for surgical treatment. The outcomes of surgery
in these patients are not yet validated and some procedures have
a high rate of complications which differ from those in patients
who do not have a MPS. The diagnosis of a MPS should be considered in adolescents or
young adults with a previously unrecognised dysplasia of the hip.
Surgeons treating patients with a MPS should report their experience
and studies should include the assessment of function and quality
of life to guide treatment. Cite this article:
Fracture repair occurs by two broad mechanisms:
direct healing, and indirect healing with callus formation. The effects
of bisphosphonates on fracture repair have been assessed only in
models of indirect fracture healing. A rodent model of rigid compression plate fixation of a standardised
tibial osteotomy was used. Ten skeletally mature Sprague–Dawley
rats received daily subcutaneous injections of 1 µg/kg ibandronate
(IBAN) and ten control rats received saline (control). Three weeks
later a tibial osteotomy was rigidly fixed with compression plating.
Six weeks later the animals were killed. Fracture repair was assessed
with mechanical testing, radiographs and histology. The mean stress at failure in a four-point bending test was significantly
lower in the IBAN group compared with controls (8.69 Nmm-2 ( Bisphosphonate treatment in a therapeutic dose, as used for risk
reduction in fragility fractures, had an inhibitory effect on direct
fracture healing. We propose that bisphosphonate therapy not be
commenced until after the fracture has united if the fracture has
been rigidly fixed and is undergoing direct osteonal healing. Cite this article:
There remains conflicting evidence regarding cortical bone strength
following bisphosphonate therapy. As part of a study to assess the
effects of bisphosphonate treatment on the healing of rat tibial
fractures, the mechanical properties and radiological density of
the uninjured contralateral tibia was assessed. Skeletally mature aged rats were used. A total of 14 rats received
1µg/kg ibandronate (iban) daily and 17 rats received 1 ml 0.9% sodium
chloride (control) daily. Stress at failure and toughness of the
tibial diaphysis were calculated following four-point bending tests.Objectives
Methods
Non-traumatic osteonecrosis of the femoral head
is a potentially devastating condition, the prevalence of which
is increasing. Many joint-preserving forms of treatment, both medical
and surgical, have been developed in an attempt to slow or reverse
its progression, as it usually affects young patients. However, it is important to evaluate the best evidence that is
available for the many forms of treatment considering the variation
in the demographics of the patients, the methodology and the outcomes
in the studies that have been published, so that it can be used
effectively. The purpose of this review, therefore, was to provide an up-to-date,
evidence-based guide to the management, both non-operative and operative,
of non-traumatic osteonecrosis of the femoral head. Cite this article:
This systematic review aimed to assess the A systematic search was performed in Pubmed, followed by a two-step selection process. We included Objectives
Methods
