Aims

Little is known about the effect of haemorrhagic shock and resuscitation on fracture healing. This study used a rabbit model with a femoral osteotomy and fixation to examine this relationship.

Objectives

Advanced glycation end-products (AGEs) are a post-translational modification of collagen that form spontaneously in the skeletal matrix due to the presence of reducing sugars, such as glucose. The accumulation of AGEs leads to collagen cross-linking, which adversely affects bone quality and has been shown to play a major role in fracture risk. Thus, intervening in the formation and accumulation of AGEs may be a viable means of protecting bone quality.

1. Previous immunological studies have shown that homografts of fresh marrow-free iliac bone are only weakly, if at all, antigenic. 2. In view of this finding an attempt was made to produce a foreign bone graft capable of forming new bone as readily as an iliac autograft by the following method. Living cells of high osteogenic potential and of autologous type were introduced into the graft by combining homologous fresh marrow-free iliac bone with the animal's own red marrow to form a fresh composite homograft-autograft of cancellous bone. 3. Such fresh composite homograft-autografts were inserted into a muscular site in Wistar rats and removed for microscopical examination at intervals of one to seven days and at two, six and twelve weeks after transplantation. 4. It is found that bone and marrow together as a fresh composite homograft-autograft form considerably more new bone than do either of the components of the graft transplanted separately. Homografts of fresh marrow-free iliac bone form, in general, a small amount of early phase and late phase new bone. Autografts of red marrow transplanted alone to a muscular site formed new bone in thirteen to thirty experiments (43 per cent). 5. The stimulus to osteogenesis, and the cellular source of osteoblasts, in marrow autografts is discussed in the light of present knowledge. The concept is suggested that after its transplantation there develops in marrow an inductive system leading to osteoblastic differentiation and bone formation. It is proposed that the necrosis of a portion of a marrow graft liberates osteogenic substances which are taken up by primitive wandering cells derived from littoral cells lining the vascular sinusoids of the surviving portions of the marrow which are induced, thereby, to differentiate as osteoblasts. 6. The cellular source of osteoblasts in a fresh composite homograft-autograft of cancellous bone is discussed. It is deduced that the new bone is derived mainly from the contained marrow of the graft, by mechanisms similar to those leading to osteoblastic differentiation in transplanted autografts of marrow. 7. The stimulus to the greater formation of new bone by fresh composite autograft-homografts than by autografts of marrow transplanted alone is discussed. Two explanations are suggested: 1) a more extensive necrosis of marrow in a composite homograft-autograft than in marrow transplanted alone; and 2) an inductive effect of bone upon marrow. 8. The new bone formed by autografts of fresh marrow-containing iliac bone, it is concluded, is derived not only from osteoblasts on the surfaces of the grafted bone but also from primitive wandering cells derived from littoral cells lining the vascular sinusoids of the surviving portions of its marrow. 9. Mechanisms which may play a role in the histogenesis of woven bone are discussed. 10. The significance of the relation of bone and marrow is considered briefly in the light of knowledge concerning the venous patterns of bone and marrow

1. The present study is an attempt to analyse and apportion significance to the role of inductive mechanisms in bone transplantation. 2. The experimental model used in the present work is that of the composite homograftautograft of cancellous bone previously described (Burwell 1964a). 3. Iliac bone was removed from hooded rats and washed free from its marrow. The bone was then treated by various physical and chemical methods (some of which have been used by other workers to prepare bank bone), namely freezing (-20 degrees Centigrade, -79 degrees Centigrade, -196 degrees Centigrade); freeze-drying (without sterilisation, sterilisation with high energy radiation, sterilisation with ß-propiolactone); decalcification (with E.D.T.A.); irradiation (in the frozen state at a dose of 4 million rads); boiling in water; immersion in merthiolate solution; extraction of organic components with ethylenediamine: and calcining at 660 degrees Centigrade. The treated bone was then impregnated with fresh autologous marrow procured from the femoral shaft of the Wistar rat into which the treated composite graft was to be implanted. The grafts were inserted intramuscularly and removed for study after two, six and twelve weeks. 4. After fixation, serial sectioning and staining, each graft was examined microscopically, and the proportion of new bone/grafted bone scored using an arbitrary scale (0-4). The mean score (and the standard error of the mean score) was then plotted for each treated composite graft and also for several types of fresh cancellous bone grafts. 5. It was found (Fig. 2) that the various treated composite grafts formed a spectrum of bone-forming capacities–the maximum scores being attained by the frozen and freeze-dried composite grafts, the lowest scores by the "deproteinised" composite grafts. 6. The reasons for these differences are discussed. It is concluded that cancellous bone, after transplantation, has the property to induce and promote osteogenesis in marrow; moreover, that this property is contained in the organic components of bone. 7. From the standpoint of inductive mechanisms, cancellous bone treated by freezing or freeze-drying seems to be the most suitable devitalised bone for grafting purposes; bone which has been boiled or merthiolated less suitable; and "deproteinised" bone the least suitable. 8. Freeze-dried bone sterilised physically (by high energy radiation) or chemically (by ß-propiolactone) did not form significantly less new bone than did freeze-dried bone which had not been sterilised. 9. Remodelling mechanisms in bone transplantation are briefly discussed and attention drawn to the deficiencies of present knowledge. The quantitative studies of other workers have indicated that freeze-dried bone may be more rapidly remodelled than is frozen bone. 10. The importance of fresh red marrow in promoting osteogenesis in bone transplantation and in the healing of certain fractures, is emphasised. It seems likely that the interrelationship of bone and marrow revealed by experiment has wider significance not only in health and in response to injury but also in causation of certain idiopathic bone disorders

Objectives

Intra-articular injections of local anaesthetics (LA), glucocorticoids (GC), or hyaluronic acid (HA) are used to treat osteoarthritis (OA). Contrast agents (CA) are needed to prove successful intra-articular injection or aspiration, or to visualize articular structures dynamically during fluoroscopy. Tranexamic acid (TA) is used to control haemostasis and prevent excessive intra-articular bleeding. Despite their common usage, little is known about the cytotoxicity of common drugs injected into joints. Thus, the aim of our study was to investigate the effects of LA, GC, HA, CA, and TA on the viability of primary human chondrocytes and tenocytes in vitro.

Long non-coding RNAs (lncRNAs) are transcripts longer than 200 nucleotides with limited coding potential, which have emerged as novel regulators in many biological and pathological processes, including growth, development, and oncogenesis. Accumulating evidence suggests that lncRNAs have a special role in the osteogenic differentiation of various types of cell, including stem cells from different sources such as embryo, bone marrow, adipose tissue and periodontal ligaments, and induced pluripotent stem cells. Involved in complex mechanisms, lncRNAs regulate osteogenic markers and key regulators and pathways in osteogenic differentiation. In this review, we provide insights into the functions and molecular mechanisms of lncRNAs in osteogenesis and highlight their emerging roles and clinical value in regenerative medicine and osteogenesis-related diseases.

Cite this article: J. Zhang, X. Hao, M. Yin, T. Xu, F. Guo. Long non-coding RNA in osteogenesis: A new world to be explored. Bone Joint Res 2019;8:73–80. DOI: 10.1302/2046-3758.82.BJR-2018-0074.R1.

Objectives

Prosthetic joint infection (PJI) is a devastating complication following total joint arthroplasty. Non-contact induction heating of metal implants is a new and emerging treatment for PJI. However, there may be concerns for potential tissue necrosis. It is thought that segmental induction heating can be used to control the thermal dose and to limit collateral thermal injury to the bone and surrounding tissues. The purpose of this study was to determine the thermal dose, for commonly used metal implants in orthopaedic surgery, at various distances from the heating centre (HC).

Objectives

Osteoporosis is a metabolic disease resulting in progressive loss of bone mass as measured by bone mineral density (BMD). Physical exercise has a positive effect on increasing or maintaining BMD in postmenopausal women. The contribution of exercise to the regulation of osteogenesis in osteoblasts remains unclear. We therefore investigated the effect of exercise on osteoblasts in ovariectomized mice.

Objectives

Emerging evidence indicates that tendon disease is an active process with inflammation that is critical to disease onset and progression. However, the key cytokines responsible for driving and sustaining inflammation have not been identified.

Objective

In the present study, we aimed to assess whether gelatin/β-tricalcium phosphate (β-TCP) composite porous scaffolds could be used as a local controlled release system for vancomycin. We also investigated the efficiency of the scaffolds in eliminating infections and repairing osteomyelitis defects in rabbits.

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

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

Recently, the field of tissue engineering has made numerous advances towards achieving artificial tendon substitutes with excellent mechanical and histological properties, and has had some promising experimental results. The purpose of this systematic review is to assess the efficacy of tissue engineering in the treatment of tendon injuries.

Objectives

Distraction osteogenesis (DO) mobilises bone regenerative potential and avoids the complications of other treatments such as bone graft. The major disadvantage of DO is the length of time required for bone consolidation. Mesenchymal stem cells (MSCs) have been used to promote bone formation with some good results.

Compartment syndrome, a devastating consequence of limb trauma, is characterised by severe tissue injury and microvascular perfusion deficits. We hypothesised that leucopenia might provide significant protection against microvascular dysfunction and preserve tissue viability. Using our clinically relevant rat model of compartment syndrome, microvascular perfusion and tissue injury were directly visualised by intravital video microscopy in leucopenic animals. We found that while the tissue perfusion was similar in both groups (38.8% (standard error of the mean (sem) 7.1), 36.4% (sem 5.7), 32.0% (sem 1.7), and 30.5% (sem 5.35) continuously-perfused capillaries at 45, 90, 120 and 180 minutes compartment syndrome, respectively versus 39.2% (sem 8.6), 43.5% (sem 8.5), 36.6% (sem 1.4) and 50.8% (sem 4.8) at 45, 90, 120 and 180 minutes compartment syndrome, respectively in leucopenia), compartment syndrome-associated muscle injury was significantly decreased in leucopenic animals (7.0% (sem 2.0), 7.0%, (sem 1.0), 9.0% (sem 1.0) and 5.0% (sem 2.0) at 45, 90, 120 and 180 minutes of compartment syndrome, respectively in leucopenia group versus 18.0% (sem 4.0), 23.0% (sem 4.0), 32.0% (sem 7.0), and 20.0% (sem 5.0) at 45, 90, 120 and 180 minutes of compartment syndrome in control, p = 0.0005). This study demonstrates that the inflammatory process should be considered central to the understanding of the pathogenesis of cellular injury in compartment syndrome.

Cite this article: Bone Joint J 2015;97-B:539–43

Osteoporosis is a systemic skeletal disorder characterized by reduced bone mass and deterioration of bone microarchitecture, which results in increased bone fragility and fracture risk. Casein kinase 2-interacting protein-1 (CKIP-1) is a protein that plays an important role in regulation of bone formation. The effect of CKIP-1 on bone formation is mainly mediated through negative regulation of the bone morphogenetic protein pathway. In addition, CKIP-1 has an important role in the progression of osteoporosis. This review provides a summary of the recent studies on the role of CKIP-1 in osteoporosis development and treatment.

Cite this article: X. Peng, X. Wu, J. Zhang, G. Zhang, G. Li, X. Pan. The role of CKIP-1 in osteoporosis development and treatment. Bone Joint Res 2018;7:173–178. DOI: 10.1302/2046-3758.72.BJR-2017-0172.R1.

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.

Aims

Compartment syndrome results from increased intra-compartmental pressure (ICP) causing local tissue ischaemia and cell death, but the systemic effects are not well described. We hypothesised that compartment syndrome would have a profound effect not only on the affected limb, but also on remote organs.

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."

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. Bone Joint Res 2018;7:232–243. DOI: 10.1302/2046-3758.73.BJR-2017-0270.R1.