Periprosthetic osteolysis is a major cause of aseptic loosening in artificial joint replacement. It is assumed to occur in conjunction with the activation of macrophages. We have shown in vitro that human osteoblast-like cells, isolated from bone specimens obtained from patients undergoing hip replacement, phagocytose fine particles of titanium alloy (TiAlV). The human osteoblast-like cells were identified immunocytochemically by the presence of bone-specific alkaline phosphatase (BAP). With increasing duration of culture, a variable number of the osteoblastic cells became positive for the macrophage marker CD68, independent of the phagocytosis of particles, with a fine granular cytoplasmic staining which was coexpressed with BAP as revealed by immunodoublestaining. The metal particles were not toxic to the osteoblastic cells since even in culture for up to four weeks massively laden cells were vital and had a characteristic morphology. Cells of the human osteosarcoma cell line (HOS 58) were also able to phagocytose metal particles but had only a low expression of the CD68 antigen. Fluorescence-activated cell scanning confirmed our immunocytochemical results. Additionally, the cells were found to be negative for the major histocompatibility complex-II (MHC-II) which is a marker for macrophages and other antigen-presenting cells. Negative results of histochemical tests for tartrate-resistant acid phosphatase excluded the contamination by osteoclasts or macrophages in culture. Our observations suggest that the osteoblast can either change to a phagocytosing cell or that the phagocytosis is an underestimated property of the osteoblast. The detection of the CD68 antigen is insufficient to prove the monocytic lineage. In order to discriminate between macrophages and osteoblasts additional markers should be used. To our knowledge, this is the first demonstration of cells of an osteoblastic origin which have acquired a mixed phenotype of both osteoblasts and macrophages

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The aim of this study was to describe the use of 3D-printed sacral endoprostheses to reconstruct the pelvic ring and re-establish spinopelvic stability after total en bloc sacrectomy (TES) and to review its outcome.

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This study aimed to evaluate the incidence and prognosis of patients with spinal metastasis as the initial manifestation of malignancy (SM-IMM).

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We retrospectively report our experience of managing 30 patients with a primary malignant tumour of the distal tibia; 25 were treated by limb salvage surgery and five by amputation. We compared the clinical outcomes of following the use of different methods of reconstruction.

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The aim of this study was to analyze the complications and outcomes of treatment in a series of previously untreated patients with a primary aneurysmal bone cyst (ABC) who had been treated by percutaneous sclerosant therapy using polidocanol.

1. Alkaline and acid phosphatase, non-specific esterase and beta-glucuronidase have been estimated and demonstrated histochemically in a series of bone tumours and allied lesions, of which ten were osteogenic sarcomata, ten were giant-cell lesions, eleven were fibroblastic lesions and seven were tumours of cartilage. 2. Osteogenic sarcoma was found to be characterised by high levels of alkaline phosphatase, with rich staining for this enzyme in the tumour cells. Similar high levels of alkaline phosphatase were found in other bone-forming lesions, such as fibrous dysplasia, a giant-cell sarcoma with osteogenic matrix, and fracture callus. 3. Giant-cell lesions were characterised by high levels of acid phosphatase, and intense staining for this enzyme in the osteoclasts. These cells were also found to be rich in non-specific esterase (as shown by the alpha-naphthyl acetate method) and in beta-glucuronidase, but almost or entirely lacking in alkaline phosphatase. High levels of alkaline phosphatase were not found in giant-cell lesions except in relation to osteogenic matrix. 4. Fibroblastic tumours were characterised by moderate levels of all four enzymes, with little or no staining for phosphatases in the tumour cells; non-specific esterase was generally present in a proportion of the cells. 5. In certain lesions intermediate stages in the differentiation of fibroblasts to osteoblasts were found, notably in fibrous dysplasia, in which the biochemical change preceded the histological. In such lesions high total levels of alkaline phosphatase were found. 6. Cartilaginous tumours were characterised by low levels of all four enzymes, and little histochemical staining except in hypertrophied cells in areas of ossification. 7. It was found in general that the enzyme distributions in these neoplasms and other lesions reflected the findings in comparable reactive and growing normal tissues

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This study aimed to uncover the hub long non-coding RNAs (lncRNAs) differentially expressed in osteoarthritis (OA) cartilage using an integrated analysis of the competing endogenous RNA (ceRNA) network and co-expression network.

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The primary aim of this study was to determine the effect of the duration of symptoms (DOS) prior to diagnosis on the overall survival in patients with a primary bone sarcoma.

Cell therapies hold significant promise for the treatment of injured or diseased musculoskeletal tissues. However, despite advances in research, there is growing concern about the increasing number of clinical centres around the world that are making unwarranted claims or are performing risky biological procedures. Such providers have been known to recommend, prescribe, or deliver so called ‘stem cell’ preparations without sufficient data to support their true content and efficacy. In this annotation, we outline the current environment of stem cell-based treatments and the strategies of marketing directly to consumers. We also outline the difficulties in the regulation of these clinics and make recommendations for best practice and the identification and reporting of illegitimate providers.

Cite this article: Bone Joint J 2020;102-B(2):148–154

Aims

Aseptic loosening is a major cause of failure in cemented endoprosthetic reconstructions. This paper presents the long-term outcomes of a custom-designed cross-pin fixation construct designed to minimize rotational stress and subsequent aseptic loosening in selected patients. The paper will also examine the long-term survivorship and modes of failure when using this technique.

1. Chondrosarcoma is a malignant tumour of bone with clinical and morphological features which distinguish it from osteosarcoma. 2. Cartilage tumours present an unbroken spectrum in their clinical behaviour and histological appearances from the entirely benign to the frankly malignant. 3. A few chondrosarcomata, particularly those in children and young adults, run a rapidly fatal course but in general they metastasise late and some kill by local extension of the tumour. 4. "Secondary" chondrosarcomata arising from a pre-existing osteocartilaginous exostosis or enchondroma are mostly low grade tumours. 5. The first appearance of an osteocartilaginous exostosis after skeletal maturity, renewed growth, or pain unassociated with a fracture, should arouse suspicion of malignancy in any cartilage tumour. 6. Cartilage tumours of the trunk and upper end of femur and humerus are especially liable to sarcomatous change. 7. Although most benign cartilage tumours occur in the hand and foot they rarely become malignant with the exception of those in the calcaneus. 8. If biopsy is necessary it should be of the incisional type, a generous amount of material being removed from the edge of the tumour. Calcified, degenerate areas must be avoided. 9. In low grade tumours microscopic fields judged to be malignant by Lichtenstein and Jaffe's well established criteria may be scanty and many paraffin sections should be examined. Absence of mitotic figures, heavy calcification and poor vascularity are no guarantee of benignity. 10. Information as to the site of the tumour and age of the patient must be available to the pathologist if a useful report is to be given. 11 . In "borderline" tumours or where any difficulty in diagnosis arises the clinical, radiographic and histological features must all be taken into account and treatment based on the most unfavourable features. 12. Chondrosarcoma is a radio-resistant tumour and treatment is by radical excision or amputation. 13. Malignant cartilage cells implanted in the tissues at operation will often continue to grow and in all instances the biopsy wound and surrounding tissues must be removed en bloc with the tumour. 14. Small, low grade, readily accessible, peripheral tumours may be successfully treated by excision with a wide margin of healthy tissue. 15. In the limbs or pelvis large tumours and those of high grade malignancy should be treated by amputation. Since marrow permeation is often greater than the radiograph suggests amputation should, as a rule, not be performed through the bone in which the chondrosarcoma is situated. 16. Recurrence carries the danger that an initially accessible tumour becomes inaccessible and inoperable and, less frequently, a low grade tumour recurs in a metastasising form. 17. Recurrence is frequent after inadequate surgery; it indicates that the tumour is at least locally malignant and a cure can usually only then be achieved by more radical surgery

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Computer-based applications are increasingly being used by orthopaedic surgeons in their clinical practice. With the integration of technology in surgery, augmented reality (AR) may become an important tool for surgeons in the future. By superimposing a digital image on a user’s view of the physical world, this technology shows great promise in orthopaedics. The aim of this review is to investigate the current and potential uses of AR in orthopaedics.

Objectives

MicroRNAs (miRNAs) have been reported as key regulators of bone formation, signalling, and repair. Fracture healing is a proliferative physiological process where the body facilitates the repair of a bone fracture. The aim of our study was to explore the effects of microRNA-186 (miR-186) on fracture healing through the bone morphogenetic protein (BMP) signalling pathway by binding to Smad family member 6 (SMAD6) in a mouse model of femoral fracture.

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We present a retrospective review of patients treated with extracorporeally irradiated allografts for primary and secondary bone tumours with the mid- and long-term survivorship and the functional and radiographic outcomes.