Aims

The success of anterior cruciate ligament reconstruction (ACLR) depends on osseointegration at the graft-tunnel interface and intra-articular ligamentization. Our aim was to conduct a systematic review of clinical and preclinical studies that evaluated biological augmentation of graft healing in ACLR.

Objectives

Cellular movement and relocalisation are important for many physiologic properties. Local mesenchymal stem cells (MSCs) from injured tissues and circulating MSCs aid in fracture healing. Cytokines and chemokines such as Stromal cell-derived factor 1(SDF-1) and its receptor chemokine receptor type 4 (CXCR4) play important roles in maintaining mobilisation, trafficking and homing of stem cells from bone marrow to the site of injury. We investigated the differences in migration of MSCs from the femurs of young, adult and ovariectomised (OVX) rats and the effect of CXCR4 over-expression on their migration.

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 in vitro cell culture have near-term promise for use in bone regenerative medicine. This narrative review presents a rationale for using EVs to improve the repair of large bone defects, highlights promising cell sources and likely therapeutic targets for directing repair through an endochondral pathway, and discusses current barriers to clinical translation.

Cite this article: E. Ferreira, R. M. Porter. Harnessing extracellular vesicles to direct endochondral repair of large bone defects. Bone Joint Res 2018;7:263–273. DOI: 10.1302/2046-3758.74.BJR-2018-0006.

1 . The magnitude of the problem of congenital anomalies becomes evident when one takes into consideration the fact that they cause the death of approximately one quarter of the human race either before or shortly after birth, and handicap an appreciable proportion of the survivors throughout their lives. Further, a significant percentage of infants judged to be normal at birth are found in later life to suffer from "disguised" anomalies of the skeleton and soft tissues. Though the study of genetic factors leading to congenital defects has attracted a great deal of attention during the last few decades, the importance of environmental causes of human malformations has received relatively less emphasis. The association of congenital anomalies such as cataract and cardiac septal defects with maternal intercurrent infection of rubella during the early months of pregnancy demonstrates clearly that changes in the germplasm cannot always be invoked as the cause of developmental abnormalities. Congenital malformations that are sometimes genetically determined, such as microphthalmos, cleft palate, and certain skeletal abnormalities, can be caused in the offspring not only by maternal nutritional deficiencies and x-radiation but also, at least in some animals, such as chickens, rats and rabbits, by the introduction of certain substances like insulin into the environment of the embryo during its development. 2. Since very little is known of the detailed histology of the early human embryo, the histological examination of cases of perverted growth is mainly limited to aborted foetuses which, unfortunately, tend to present varying degrees of post-mortem degeneration before accurate histological methods can be applied. It is exactly in this field that animal experiments can offer valuable help. According to Mall and other embryologists the pathological changes that take place in human foetuses and those obtained experimentally in animals are not merely "analogous or similar but identical.". 3. An attempt has been made to review, in some detail, the more important work which has been carried out on experimental teratogenesis, on the epidemiological implications of developmental arrests in humans, and on foetal abnormalities associated with maternal metabolic and hormonal disorders during pregnancy. 4. The technique employed for injection of insulin into the egg yolk has been described. Methods used for the estimation of blood sugar in chick embryos at various stages after injection of insulin and special histochemical techniques for localising polysaccharides in cartilage have been outlined. 5. A few salient experimental results have been tabulated, and some of the insulin-induced abnormalities have been illustrated. 6. The possible mechanism of action of insulin in the causation of the various developmental anomalies has been discussed. Broadly speaking, insulin seems to affect primarily the part or tissue which is in the most active stage of growth or differentiation at the time of the injection. Within the range of 0·05 to 6 units of insulin employed, the incidence, severity and distribution of the deformities appear to increase with the dose of the hormone. It has been observed that the hypoglycaemia caused by insulin injection is not counteracted till about the twelfth day of incubation, presumably because of excessive accumulation of glycogen in the yolk-sac membrane immediately after the injection, and because of lack of glycogen storage in the embryonic liver and the absence of active secretion in the endocrine glands concerned with the carbohydrate metabolism of the embryo. It has been suggested that this unchecked hypoglycaemia may deprive the mesenchyme, pre-cartilage and cartilage of glycogen and mucopolysaccharides (chondroiten-sulphuric acid complexes), depending on the time of injection and the dose of insulin, and thus not only give rise to a variety of single and multiple deformities in the cartilaginous skeleton but also interfere with the normal endochondral ossification, resulting in a generalised developmental disturbance of bone resembling osteogenesis imperfecta in the human. 7. Insulin-induced abnormalities can be prevented to a remarkable extent by injecting nicotinamide and riboflavin into eggs along with insulin. 8. The question of the practical application of the knowledge gained from experimental observations on insulin-induced developmental abnormalities in explaining the possible causation of congenital anomalies in humans by genetic and environmental teratogenic factors, has been discussed. It is suggested that the orderly progression from the mesenchymatous condensation to cartilage, and then through calcified cartilage to bone, may be disturbed by these teratogenic factors at critical phases during the development of the embryo, and a variety of single and multiple skeletal deformities may thus be induced. 9. A plea is made for routine pathological and radiological examination of aborted foetuses and stillborn infants more or less on the lines followed for experimentally induced deformities with a view to applying the knowledge gained from animal experiments to a better understanding of the etiology and pathology of human congenital anomalies. 10. As regards the possible prevention of these deformities, it is not always easy to offer sound eugenic advice in the cases of congenital malformations determined partly or completely by genetic factors, for two important reasons. First, it is often difficult to distinguish between genetically determined congenital anomalies and their phenocopies. Secondly, genetically determined developmental defects sometimes show surprisingly variable expressivity and penetrance. For the conditions in which both genetic and environmental factors are involved, the most profitable immediate line of attack would be on the environmental factors. A relatively simpler problem is presented by the malformations which are, for all practical purposes, entirely caused by environmental factors. Measures to prevent congenital anomalies caused by prenatal rubella, such as exposure of girls to the disease during childhood and protection of pregnant women during the early stages of pregnancy by immune serum, are under active consideration. 11 . Further energetic investigation of the causes of permaturity, stillbirths, monstrosities and congenital malformations is urgently needed, before embarking on a successful programme for prevention. "The day of successful prophylaxis is not yet, but it is much nearer than seemed possible a few years ago."

Objectives

Cortical and cancellous bone healing processes appear to be histologically different. They also respond differently to anti-inflammatory agents. We investigated whether the leucocyte composition on days 3 and 5 after cortical and cancellous injuries to bone was different, and compared changes over time using day 3 as the baseline.

Objectives

This systematic review aimed to assess the in vivo and clinical effect of strontium (Sr)-enriched biomaterials in bone formation and/or remodelling.

Aims

The aim of this double-blind prospective randomised controlled trial was to assess whether low intensity pulsed ultrasound (LIPUS) accelerated or enhanced the rate of bone healing in adult patients undergoing distraction osteogenesis.

Objectives

Researchers continue to seek easier ways to evaluate the quality of bone and screen for osteoporosis and osteopenia. Until recently, radiographic images of various parts of the body, except the distal femur, have been reappraised in the light of dual-energy X-ray absorptiometry (DXA) findings. The incidence of osteoporotic fractures around the knee joint in the elderly continues to increase. The aim of this study was to propose two new radiographic parameters of the distal femur for the assessment of bone quality.

Aims

The management of a significant bony defect following excision of a diaphyseal atrophic femoral nonunion remains a challenge. We present the outcomes using a combined technique of acute femoral shortening, stabilized with a long retrograde intramedullary nail, accompanied by bifocal osteotomy compression and distraction osteogenesis with a temporary monolateral fixator.

Objectives

Osteophytes are products of active endochondral and intramembranous ossification, and therefore could theoretically provide significant efficacy as bone grafts. In this study, we compared the bone mineralisation effectiveness of osteophytes and cancellous bone, including their effects on secretion of growth factors and anabolic effects on osteoblasts.

Objectives

Pulsed electromagnetic field (PEMF) stimulation was evaluated after anterior cervical discectomy and fusion (ACDF) procedures in a randomized, controlled clinical study performed for United States Food and Drug Administration (FDA) approval. PEMF significantly increased fusion rates at six months, but 12-month fusion outcomes for subjects at elevated risk for pseudoarthrosis were not thoroughly reported. The objective of the current study was to evaluate the effect of PEMF treatment on subjects at increased risk for pseudoarthrosis after ACDF procedures.

The development and pre-clinical evaluation of nano-texturised, biomimetic, surfaces of titanium (Ti) implants treated with titanium dioxide (TiO₂) nanotube arrays is reviewed. In vitro and in vivo evaluations show that TiO₂ nanotubes on Ti surfaces positively affect the osseointegration, cell differentiation, mineralisation, and anti-microbial properties. This surface treatment can be superimposed onto existing macro and micro porous Ti implants creating a surface texture that also interacts with cells at the nano level. Histology and mechanical pull-out testing of specimens in rabbits indicate that TiO₂ nanotubes improves bone bonding nine-fold (p = 0.008). The rate of mineralisation associated with TiO₂ nanotube surfaces is about three times that of non-treated Ti surfaces. In addition to improved osseointegration properties, TiO₂ nanotubes reduce the initial adhesion and colonisation of Staphylococcus epidermidis. Collectively, the properties of Ti implant surfaces enhanced with TiO₂ nanotubes show great promise.

Cite this article: Bone Joint J 2018;100-B(1 Supple A):9–16.

In vivo animal experimentation has been one of the cornerstones of biological and biomedical research, particularly in the field of clinical medicine and pharmaceuticals. The conventional in vivo model system is invariably associated with high production costs and strict ethical considerations. These limitations led to the evolution of an ex vivo model system which partially or completely surmounted some of the constraints faced in an in vivo model system. The ex vivo rodent bone culture system has been used to elucidate the understanding of skeletal physiology and pathophysiology for more than 90 years. This review attempts to provide a brief summary of the historical evolution of the rodent bone culture system with emphasis on the strengths and limitations of the model. It encompasses the frequency of use of rats and mice for ex vivo bone studies, nutritional requirements in ex vivo bone growth and emerging developments and technologies. This compilation of information could assist researchers in the field of regenerative medicine and bone tissue engineering towards a better understanding of skeletal growth and development for application in general clinical medicine.

Cite this article: A. A. Abubakar, M. M. Noordin, T. I. Azmi, U. Kaka, M. Y. Loqman. The use of rats and mice as animal models in ex vivo bone growth and development studies. Bone Joint Res 2016;5:610–618. DOI: 10.1302/2046-3758.512.BJR-2016-0102.R2.

Objectives

The primary purpose of this meta-analysis was to determine whether statin usage could reduce the risk of glucocorticoid-related osteonecrosis in animal models.

Objectives

Ultraviolet (UV) light-mediated photofunctionalisation is known to improve osseointegration of pure titanium (Ti). However, histological examination of titanium alloy (Ti6Al4V), which is frequently applied in orthopaedic and dental surgery, has not yet been performed. This study examined the osseointegration of photofunctionalised Ti6Al4V implants.

Objectives

The objective of this study was to investigate the therapeutic effect of peripheral blood mononuclear cells (PBMNCs) treated with quality and quantity control culture (QQ-culture) to expand and fortify angiogenic cells on the acceleration of fracture healing.

Aims

This study describes the use of the Masquelet technique to treat segmental tibial bone loss in 12 patients.

Construction of a functional skeleton is accomplished through co-ordination of the developmental processes of chondrogenesis, osteogenesis, and synovial joint formation. Infants whose movement in utero is reduced or restricted and who subsequently suffer from joint dysplasia (including joint contractures) and thin hypo-mineralised bones, demonstrate that embryonic movement is crucial for appropriate skeletogenesis. This has been confirmed in mouse, chick, and zebrafish animal models, where reduced or eliminated movement consistently yields similar malformations and which provide the possibility of experimentation to uncover the precise disturbances and the mechanisms by which movement impacts molecular regulation. Molecular genetic studies have shown the important roles played by cell communication signalling pathways, namely Wnt, Hedgehog, and transforming growth factor-beta/bone morphogenetic protein. These pathways regulate cell behaviours such as proliferation and differentiation to control maturation of the skeletal elements, and are affected when movement is altered. Cell contacts to the extra-cellular matrix as well as the cytoskeleton offer a means of mechanotransduction which could integrate mechanical cues with genetic regulation. Indeed, expression of cytoskeletal genes has been shown to be affected by immobilisation. In addition to furthering our understanding of a fundamental aspect of cell control and differentiation during development, research in this area is applicable to the engineering of stable skeletal tissues from stem cells, which relies on an understanding of developmental mechanisms including genetic and physical criteria. A deeper understanding of how movement affects skeletogenesis therefore has broader implications for regenerative therapeutics for injury or disease, as well as for optimisation of physical therapy regimes for individuals affected by skeletal abnormalities.

Cite this article: Bone Joint Res 2015;4:105–116

This review explores recent advances in fixator design and used in contemporary orthopaedic practice including the management of bone loss, complex deformity and severe isolated limb injury.

Aims

We reviewed 34 consecutive patients (18 female-16 male) with isthmic spondylolysis and grade I to II lumbosacral spondylolisthesis who underwent in situ posterolateral arthodesis between the L5 transverse processes and the sacral ala with the use of iliac crest autograft. Ten patients had an associated scoliosis which required surgical correction at a later stage only in two patients with idiopathic curves unrelated to the spondylolisthesis.