Bisphosphonates (BP) are the first-line treatment for preventing fragility fractures. However, concern regarding their efficacy is growing because bisphosphonate is associated with over-suppression of remodelling and accumulation of microcracks. While dual-energy X-ray absorptiometry (DXA) scanning may show a gain in bone density, the impact of this class of drug on mechanical properties remains unclear. We therefore sought to quantify the mechanical strength of bone treated with BP (oral alendronate), and correlate data with the microarchitecture and density of microcracks in comparison with untreated controls. Trabecular bone from hip fracture patients treated with BP (n = 10) was compared with naïve fractured (n = 14) and non-fractured controls (n = 6). Trabecular cores were synchrotron scanned and micro-CT scanned for microstructural analysis, including quantification of bone volume fraction, microarchitecture and microcracks. The specimens were then mechanically tested in compression.Objectives
Methods
Demineralised bone matrix (DBM) is rarely used for the local
delivery of prophylactic antibiotics. Our aim, in this study, was
to show that a graft with a bioactive glass and DBM combination,
which is currently available for clinical use, can be loaded with
tobramycin and release levels of antibiotic greater than the minimum
inhibitory concentration for Antibiotic was loaded into a graft and subsequently evaluated
for drug elution kinetics and the inhibition of bacterial growth.
A rat femoral condylar plug model was used to determine the effect
of the graft, loaded with antibiotic, on bone healing.Aims
Materials and Methods
The lack of effective treatment for cartilage defects has prompted investigations using tissue engineering techniques for their regeneration and repair. The success of tissue-engineered repair of cartilage may depend on the rapid and efficient adhesion of transplanted cells to a scaffold. Our aim in this study was to repair full-thickness defects in articular cartilage in the weight-bearing area of a porcine model, and to investigate whether the CD44 monoclonal antibody biotin-avidin (CBA) binding technique could provide satisfactory tissue-engineered cartilage. Cartilage defects were created in the load-bearing region of the lateral femoral condyle of mini-type pigs. The defects were repaired with traditional tissue-engineered cartilage, tissue-engineered cartilage constructed with the biotin-avidin (BA) technique, tissue-engineered cartilage constructed with the CBA technique and with autologous cartilage. The biomechanical properties, Western blot assay, histological findings and immunohistochemical staining were explored.Objectives
Methods
During the last decades, several research groups have used bisphosphonates for local application to counteract secondary bone resorption after bone grafting, to improve implant fixation or to control bone resorption caused by bone morphogenetic proteins (BMPs). We focused on zoledronate (a bisphosphonate) due to its greater antiresorptive potential over other bisphosphonates. Recently, it has become obvious that the carrier is of importance to modulate the concentration and elution profile of the zoledronic acid locally. Incorporating one fifth of the recommended systemic dose of zoledronate with different apatite matrices and types of bone defects has been shown to enhance bone regeneration significantly
The aim of this study was to investigate the structural integrity of torn and non-torn human acetabular labral tissue. A total of 47 human labral specimens were obtained from a biobank. These included 22 torn specimens and 25 control specimens from patients undergoing total hip arthroplasty with macroscopically normal labra. The specimens underwent dynamic shear analysis using a rheometer to measure storage modulus, as an indicator of structural integrity.Objectives
Methods
We have assessed the different adhesive properties
of some of the most common bacteria associated with periprosthetic
joint infection on various types of ultra high molecular Weight
Polyethylene (UHMWPE). Quantitative Cite this article:
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.
Mesenchymal stem cells have the ability to differentiate into various cell types, and thus have emerged as promising alternatives to chondrocytes in cell-based cartilage repair methods. The aim of this experimental study was to investigate the effect of bone marrow derived mesenchymal stem cells combined with platelet rich fibrin on osteochondral defect repair and articular cartilage regeneration in a canine model. Osteochondral defects were created on the medial femoral condyles of 12 adult male mixed breed dogs. They were either treated with stem cells seeded on platelet rich fibrin or left empty. Macroscopic and histological evaluation of the repair tissue was conducted after four, 16 and 24 weeks using the International Cartilage Repair Society macroscopic and the O’Driscoll histological grading systems. Results were reported as mean and standard deviation (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
Periprosthetic joint infection (PJI) is a serious complication
of total hip arthroplasty (THA). Different bearing surface materials
have different surface properties and it has been suggested that
the choice of bearing surface may influence the risk of PJI after
THA. The objective of this meta-analysis was to compare the rate
of PJI between metal-on-polyethylene (MoP), ceramic-on-polyethylene
(CoP), and ceramic-on-ceramic (CoC) bearings. Electronic databases (Medline, Embase, Cochrane library, Web
of Science, and Cumulative Index of Nursing and Allied Health Literature)
were searched for comparative randomized and observational studies
that reported the incidence of PJI for different bearing surfaces.
Two investigators independently reviewed studies for eligibility, evaluated
risk of bias, and performed data extraction. Meta-analysis was performed
using the Mantel–Haenzel method and random-effects model in accordance
with methods of the Cochrane group.Aims
Patients and Methods
We compared the clinical and radiological outcomes of using a
polyetheretherketone cage with (TiPEEK) and without a titanium coating
(PEEK) for instrumented transforaminal lumbar interbody fusion (TLIF). We conducted a randomised clinical pilot trial of 40 patients
who were scheduled to undergo a TLIF procedure at one or two levels
between L2 and L5. The Oswestry disability index (ODI), EuroQoL-5D,
and back and leg pain were determined pre-operatively, and at three,
six, and 12 months post-operatively. Fusion rates were assessed
by thin slice CT at three months and by functional radiography at
12 months.Aims
Materials and Methods
The optimal method of tibial component fixation remains uncertain
in total knee arthroplasty (TKA). Hydroxyapatite coatings have been
applied to improve bone ingrowth in uncemented designs, but may
only coat the directly accessible surface. As peri-apatite (PA)
is solution deposited, this may increase the coverage of the implant
surface and thereby fixation. We assessed the tibial component fixation
of uncemented PA-coated TKAs Patients were randomised to PA-coated or cemented TKAs. In 60
patients (30 in each group), radiostereometric analysis of tibial
component migration was evaluated as the primary outcome at baseline,
three months post-operatively and at one, two and five years. A
linear mixed-effects model was used to analyse the repeated measurements.Aims
Patients and Methods
We evaluated clinical and radiographic outcomes of total shoulder
arthroplasty (TSA) using the second-generation Trabecular Metal
(TM) Glenoid component. The first generation component was withdrawn
in 2005 after a series of failures were reported. Between 2009 and
2012, 40 consecutive patients with unilateral TSA using the second-generation
component were enrolled in this clinical study. The mean age of
the patients was 63.8 years (40 to 75) and the mean follow-up was
38 months (24 to 42). Patients were evaluated using the Constant score (CS), the American
Shoulder and Elbow Surgeons (ASES) score and routine radiographs.Aims
Methods
In this retrospective observational cohort study,
we describe 17 patients out of 1775 treated for various fractures who
developed mycobacterium tuberculosis (MTB) infection after surgery.
The cohort comprised 15 men and two women with a mean age of 40
years (24 to 70). A total of ten fractures were open and seven were
closed. Of these, seven patients underwent intramedullary nailing
of a fracture of the long bone, seven had fractures fixed with plates,
two with Kirschner-wires and screws, and one had a hemiarthroplasty
of the hip with an Austin Moore prosthesis. All patients were followed-up
for two years. In all patients, the infection resolved, and in 14
the fractures united. Nonunion was seen in two patients one of whom
underwent two-stage total hip arthroplasty (THA) and the other patient
was treated using excision arthoplasty. Another patient was treated
using two-stage THA. With only sporadic case reports in the literature,
MTB infection is rarely clinically suspected, even in underdeveloped
and developing countries, where pulmonary and other forms of TB
are endemic. In developed countries there is also an increased incidence
among immunocompromised patients. In this paper we discuss the pathogenesis
and incidence of MTB infection after surgical management of fractures
and suggest protocols for early diagnosis and management. Cite this article:
Nanotechnology is the study, production and controlled
manipulation of materials with a grain size <
100 nm. At this
level, the laws of classical mechanics fall away and those of quantum
mechanics take over, resulting in unique behaviour of matter in
terms of melting point, conductivity and reactivity. Additionally,
and likely more significant, as grain size decreases, the ratio
of surface area to volume drastically increases, allowing for greater interaction
between implants and the surrounding cellular environment. This
favourable increase in surface area plays an important role in mesenchymal
cell differentiation and ultimately bone–implant interactions. Basic science and translational research have revealed important
potential applications for nanotechnology in orthopaedic surgery,
particularly with regard to improving the interaction between implants
and host bone. Nanophase materials more closely match the architecture
of native trabecular bone, thereby greatly improving the osseo-integration
of orthopaedic implants. Nanophase-coated prostheses can also reduce
bacterial adhesion more than conventionally surfaced prostheses.
Nanophase selenium has shown great promise when used for tumour
reconstructions, as has nanophase silver in the management of traumatic
wounds. Nanophase silver may significantly improve healing of peripheral
nerve injuries, and nanophase gold has powerful anti-inflammatory
effects on tendon inflammation. Considerable advances must be made in our understanding of the
potential health risks of production, implantation and wear patterns
of nanophase devices before they are approved for clinical use.
Their potential, however, is considerable, and is likely to benefit
us all in the future. Cite this article:
