MicroRNAs (miRNAs) are a class of small non-coding RNAs that have emerged as potential predictive, prognostic, and therapeutic biomarkers, relevant to many pathophysiological conditions including limb immobilization, osteoarthritis, sarcopenia, and cachexia. Impaired musculoskeletal homeostasis leads to distinct muscle atrophies. Understanding miRNA involvement in the molecular mechanisms underpinning conditions such as muscle wasting may be critical to developing new strategies to improve patient management. MicroRNAs are powerful post-transcriptional regulators of gene expression in muscle and, importantly, are also detectable in the circulation. MicroRNAs are established modulators of muscle satellite stem cell activation, proliferation, and differentiation, however, there have been limited human studies that investigate miRNAs in muscle wasting. This narrative review summarizes the current knowledge as to the role of miRNAs in the skeletal muscle differentiation and atrophy, synthesizing the findings of published data.

Cite this article: Bone Joint Res 2020;9(11):798–807.

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Arthrofibrosis is a relatively common complication after joint injuries and surgery, particularly in the knee. The present study used a previously described and validated rabbit model to assess the biomechanical, histopathological, and molecular effects of the mast cell stabilizer ketotifen on surgically induced knee joint contractures in female rabbits.

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There is a lack of evidence about the risk factors for local recurrence of a giant cell tumour (GCT) of the sacrum treated with nerve-sparing surgery, probably because of the rarity of the disease. This study aimed to answer two questions: first, what is the rate of local recurrence of sacral GCT treated with nerve-sparing surgery and second, what are the risk factors for its local recurrence?

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The study aimed to determine whether the microRNA miR21-5p (MiR21) mediates temporomandibular joint osteoarthritis (TMJ-OA) by targeting growth differentiation factor 5 (Gdf5).

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Bone demonstrates good healing capacity, with a variety of strategies being utilized to enhance this healing. One potential strategy that has been suggested is the use of stem cells to accelerate healing.

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Hospital case volume is shown to be associated with postoperative outcomes in various types of surgery. However, conflicting results of volume-outcome relationship have been reported in hip fracture surgery. This retrospective cohort study aimed to evaluate the association between hospital case volume and postoperative outcomes in patients who had hip fracture surgery. We hypothesized that higher case volume would be associated with lower risk of in-hospital and one-year mortality after hip fracture surgery.

Post-traumatic elbow stiffness is a disabling condition that remains challenging for upper limb surgeons. Open elbow arthrolysis is commonly used for the treatment of stiff elbow when conservative therapy has failed. Multiple questions commonly arise from surgeons who deal with this disease. These include whether the patient has post-traumatic stiff elbow, how to evaluate the problem, when surgery is appropriate, how to perform an excellent arthrolysis, what the optimal postoperative rehabilitation is, and how to prevent or reduce the incidence of complications. Following these questions, this review provides an update and overview of post-traumatic elbow stiffness with respect to the diagnosis, preoperative evaluation, arthrolysis strategies, postoperative rehabilitation, and prevention of complications, aiming to provide a complete diagnosis and treatment path.

Cite this article: Bone Joint Open 2020;1-9:576–584.

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Parathyroid hormone (PTH) (1-34) exhibits potential in preventing degeneration in both cartilage and subchondral bone in osteoarthritis (OA) development. We assessed the effects of PTH (1-34) at different concentrations on bone and cartilage metabolism in a collagenase-induced mouse model of OA and examined whether PTH (1-34) affects the JAK2/STAT3 signalling pathway in this process.

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This study aimed to explore whether serum combined with synovial interleukin-6 (IL-6) measurement can improve the accuracy of prosthetic joint infection (PJI) diagnosis, and to establish the cut-off values of IL-6 in serum and synovial fluid in detecting chronic PJI.

From November 1994 to March 1997, we harvested 137 grafts of the femoral head from 125 patients for donation during total hip arthroplasty according to the guidelines of the American Associations of Tissue Banks (AATB) and the European Association of Musculo-Skeletal transplantation (EAMST). In addition to the standards recommended by these authorities, we performed histopathological examination of a core biopsy of the retrieved bone allograft and of the synovium. Of the 137 allografts, 48 (35.0%) fulfilled all criteria and were free for donation; 31 (22.6%) were not regarded as suitable for transplantation because the serological retests at six months were not yet complete and 58 (42.3%) were discarded because of incomplete data. Of those discarded, five showed abnormal histopathological findings; three were highly suspicious of low-grade B-cell lymphoma, one of monoclonal plasmacytosis and the other of non-specific inflammation of bone marrow. However, according to the standards of the AATB or EAMST they all met the criteria and were eligible for transplantation. Our findings indicate that the incidence of abnormal histopathology in these retrieved allografts was 3.6%. Since it is essential to confirm the quality of donor bones in bone banking, we advise that histopathological screening of donor bone should be performed to exclude abnormal allografts

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The anterior cruciate ligament (ACL) is known to have a poor wound healing capacity, whereas other ligaments outside of the knee joint capsule such as the medial collateral ligament (MCL) apparently heal more easily. Plasmin has been identified as a major component in the synovial fluid that varies among patients. The aim of this study was to test whether plasmin, a component of synovial fluid, could be a main factor responsible for the poor wound healing capacity of the ACL.

Wear products of metal implants are known to induce biological events which may have profound consequences for the microcirculation of skeletal muscle. Using the skinfold chamber model and intravital microscopy we assessed microcirculatory parameters in skeletal muscle after confrontation with titanium and stainless-steel wear debris, comparing the results with those of bulk materials. Implantation of stainless-steel bulk and debris led to a distinct activation of leukocytes combined with a disruption of the microvascular endothelial integrity and massive leukocyte extravasation. While animals with bulk stainless steel showed a tendency to recuperation, stainless-steel wear debris induced such severe inflammation and massive oedema that the microcirculation broke down within 24 hours after implantation. Titanium bulk caused only a transient increase in leukocyte-endothelial cell interaction within the first 120 minutes and no significant change in macromolecular leakage, leukocyte extravasation or venular diameter. Titanium wear debris produced a markedly lower inflammatory reaction than stainless-steel bulk, indicating that a general benefit of bulk versus debris could not be claimed. Depending on its constituents, wear debris is capable of eliciting acute inflammation which may result in endothelial damage and subsequent failure of microperfusion. Our results indicate that not only the bulk properties of orthopaedic implants but also the microcirculatory implications of inevitable wear debris play a pivotal role in determining the biocompatibility of an implant

Experiments on white mice were undertaken to determine the reaction of bone to the intramedullary introduction of the virus of tick-borne encephalitis. The following conclusions were drawn. 1. The tick-borne encephalitis virus S47, when introduced intraosteally in white mice, provokes osteitis. 2. Inflammation may lead to acute necrosis of bone, preceded by marked medullary oedema and subsequent proliferation, or it may take a milder form with haemorrhagic effusion into the marrow tissue and subsequent hyperplasia of connective tissue. 3. Damage to the epiphysial and articular cartilage may ensue in the course of acute necrotic osteitis. 4. Skeletal and extra-skeletal osteogenesis is a characteristic feature of viral osteitis. 5. In radiographs in acute viral osteitis with extensive necrosis the expanded bone appears to be thickened. 6. Viruses of the S47 strain introduced intraosteally preserve their affinity for brain tissue after three passages through bone. 7. Viruses introduced into the bony tissue preserve their toxicity and are found in the bony tissue after ten days in quantities lethal for young mice when inoculated intracerebrally. 8. The tick-borne encephalitis virus S47 is pathogenic when inoculated into the marrow in white mice. 9. In osteitis of non-bacterial origin in man the possibility of viral infection should be considered

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Kashin-Beck disease (KBD) is a kind of chronic osteochondropathy, thought to be caused by environmental risk factors such as T-2 toxin. However, the exact aetiology of KBD remains unclear. In this study, we explored the functional relevance and biological mechanism of cartilage oligosaccharide matrix protein (COMP) in the articular cartilage damage of KBD.

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During the COVID-19 pandemic, many patients continue to require urgent surgery for hip fractures. However, the impact of COVID-19 on perioperative outcomes in these high-risk patients remains unknown. The objectives of this study were to establish the effects of COVID-19 on perioperative morbidity and mortality, and determine any risk factors for increased mortality in patients with COVID-19 undergoing hip fracture surgery.

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The lack of disease-modifying treatments for osteoarthritis (OA) is linked to a shortage of suitable biomarkers. This study combines multi-molecule synovial fluid analysis with machine learning to produce an accurate diagnostic biomarker model for end-stage knee OA (esOA).

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Femoroacetabular impingement (FAI) is a potential cause of hip osteoarthritis (OA). The purpose of this study was to investigate the expression profile of matrix metalloproteinases (MMPs) in the labral tissue with FAI pathology.

Osteoporosis (OP) is a chronic metabolic bone disease characterized by the decrease of bone tissue per unit volume under the combined action of genetic and environmental factors, which leads to the decrease of bone strength, makes the bone brittle, and raises the possibility of bone fracture. However, the exact mechanism that determines the progression of OP remains to be underlined. There are hundreds of trillions of symbiotic bacteria living in the human gut, which have a mutually beneficial symbiotic relationship with the human body that helps to maintain human health. With the development of modern high-throughput sequencing (HTS) platforms, there has been growing evidence that the gut microbiome may play an important role in the programming of bone metabolism. In the present review, we discuss the potential mechanisms of the gut microbiome in the development of OP, such as alterations of bone metabolism, bone mineral absorption, and immune regulation. The potential of gut microbiome-targeted strategies in the prevention and treatment of OP was also evaluated.

Cite this article: Bone Joint Res 2020;9(8):524–530.

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Extracellular matrix (ECM) and its architecture have a vital role in articular cartilage (AC) structure and function. We hypothesized that a multi-layered chitosan-gelatin (CG) scaffold that resembles ECM, as well as native collagen architecture of AC, will achieve superior chondrogenesis and AC regeneration. We also compared its in vitro and in vivo outcomes with randomly aligned CG scaffold.

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To explore the effect of different types of articulating antibiotic-loaded cement spacers in two-stage revision for chronic hip prosthetic joint infection (PJI).