Three normal digital flexor tendon sheaths and the corresponding tissue formed around five silicone rod tendon implants, two silicone rubber mammary prostheses and one polyethylene tubing implant have been examined by light microscopy and by transmission and scanning electron microscopy. No principal difference in morphology was found. The surface facing tendon or implant was almost invariably covered with an irregular layer of amorphous material and filaments; only occasionally were collagen fibrils or cells exposed. Beneath the surface there were abundant collagen fibrils and some cells; besides fibroblasts, cells rich in filaments and often with numerous glycogen granules, mitochondria and peripherally located vesicles were found. These cells were frequently surrounded by a thick layer of an amorphous matrix. The results indicate that the implants caused remarkably little tissue reaction

A longitudinal incision resembling a bucket-handle tear was made in the menisci of 8 rabbits, 6 dogs, 11 pigs and 12 sheep. In some of the animals of each species the cut was repaired by suturing, and in others it was not. Gross inspection, as well as examination by light and electron microscopy, showed that no healing had occurred after six months in the sutured or the unsutured wounds and that the meniscus was incapable of significant intrinsic repair. In a second experiment longitudinal, transverse and T-shaped cuts were made in the menisci of 12 sheep, and a flap of synovium was sutured into the wound. Three months later there was clear evidence of healing by the formation of cartilaginous tissue. Examination by light and electron microscopy showed that the newly formed repair tissue, possibly derived by metaplasia from the synovium, had a morphology intermediate between hyaline cartilage and fibrocartilage. Synovial implantation may therefore be considered as an alternative to meniscectomy in the management of the torn meniscus

Aims

The purpose of this study was to compare clinical results, long-term survival, and complication rates of stemless shoulder prosthesis with stemmed anatomical shoulder prostheses for treatment of osteoarthritis and to analyze radiological bone changes around the implants during follow-up.

1. Serial slices of articular cartilage obtained at necropsy from apparently normal femoral condyles of individuals between the ages of twenty-six and sixty were examined chemically, by electron microscopy and for permeability. 2. The most superficial layer was shown by chemical analysis and electron microscopy to have the highest collagen content, which fell sharply with distance from the articular surface. On the other hand the glycosaminoglycan content was very low in the superficial layers but increased with depth. This variation was found in all specimens tested but the absolute levels of collagen and of glycosaminoglycans were widely different. There was no correlation of chemical composition with age. 3. Collagen fibrils in the superficial layer were of much smaller diameter than in the deeper zones. 4. Hydraulic permeability was shown to depend more on glycosaminoglycan than on collagen content, although it varied inversely with both these factors. 5. The results obtained demonstrate clearly the close relation between the physical properties of cartilage and its chemical composition

Since the Oxford knee was first used unicompartmentally in 1982, a small number of bearings have fractured. Of 14 retrieved bearings, we examined ten samples with known durations in situ (four Phase 1, four Phase 2 and two Phase 3). Evidence of impingement and associated abnormally high wear (> 0.05 mm per year) as well as oxidation was observed in all bearings. In four samples the fracture was associated with the posterior radio-opaque wire. Fracture surfaces indicated fatigue failure, and scanning electron microscopy suggested that the crack initiated in the thinnest region. The estimated incidence of fracture was 3.20% for Phase 1, 0.74% for Phase 2, 0.35% for Phase 3, and 0% for Phase 3 without the posterior marker wire. The important aetiological factors for bearing fracture are impingement leading to high wear, oxidation, and the posterior marker wire. With improved surgical technique, impingement and high wear should be prevented and modern polyethylene may reduce the oxidation risk. A posterior marker wire is no longer used in the polyethylene meniscus. Therefore, the rate of fracture, which is now very low, should be reduced to a negligible level

In laboratory tests, the ultra-high molecular weight polyethylene used for the acetabular cups of Charnley hip prostheses has a very low wear rate against steel. In the body radiographic measurements indicate that the polyethylene wears more rapidly. In order to investigate this higher wear rate, the sockets of acetabular cups removed at post-mortem have been examined using optical and electron microscopy. It has been shown that a socket wears predominantly on its superior part and that this is a direct consequence of the orientation of the cup in the body and the direction of loading of the hip. In the worn region the femoral head in effect bores out a new socket for itself, a process which is visible with the naked eye after approximately eight years. Electron microscopy shows that the predominant wear mechanism is adhesion, but after about eight years the appearance of surface cracks suggests that surface fatigue is taking place in addition to this. Laboratory wear tests have shown that pure surface fatigue is not sufficient to account for the high clinical wear rate. Other deformation processes are suggested and discussed with regard to the higher clinical wear rate

Aims

The aims of this study were to evaluate wear on the surface of cobalt-chromium (CoCr) femoral components used in total knee arthroplasty (TKA) and compare the wear of these components with that of ceramic femoral components.

Caveolae, specialised regions of the cell membrane which have been detected in a wide range of mammalian cells, have not been described in bone cells. They are plasmalemmal invaginations, 50 to 100 nm in size, characterised by the presence of the structural protein, caveolin, which exists as three subtypes. Caveolin-1 and caveolin-2 are expressed in a wide range of cell types whereas caveolin-3 is thought to be a muscle-specific subtype. There is little information on the precise function of caveolae, but it has been proposed that they play an important role in signal transduction. As the principal bone-producing cell, the osteoblast has been widely studied in an effort to understand the signalling pathways by which it responds to extracellular stimuli. Our aim in this study was to identify caveolae and their structural protein caveolin in normal human osteoblasts, and to determine which subtypes of caveolin were present. Confocal microscopy showed staining which was associated with the plasma membrane. Transmission electron microscopy revealed the presence of membrane invaginations of 50 to 100 nm, consistent with the appearance of caveolae. Finally, we isolated protein from these osteoblasts, and performed Western blotting using anti-caveolin primary antibodies. This revealed the presence of caveolin-1 and -2, while caveolin-3 was absent. The identification of these structures and their associated protein may provide a significant contribution to our further understanding of signal transduction pathways in osteoblasts

Aims

The Exeter V40 cemented polished tapered stem system has demonstrated excellent long-term outcomes. This paper presents a systematic review of the existing literature and reports on a large case series comparing implant fractures between the Exeter V40 series; 125 mm and conventional length stem systems.

Aims

Rotator cuff (RC) tears are common musculoskeletal injuries which often require surgical intervention. Noninvasive pulsed electromagnetic field (PEMF) devices have been approved for treatment of long-bone fracture nonunions and as an adjunct to lumbar and cervical spine fusion surgery. This study aimed to assess the effect of continuous PEMF on postoperative RC healing in a rat RC repair model.

1. Methods for culturing cells isolated from slices of arthritic human or normal mammalian cancellous bone are described. 2. The capacity of the cultured cells to take up and hydroxylate labelled proline has been investigated. 3. Sections of the partially decalcified bone and of the isolated cells have been examined by transmission electron microscopy. 4. The possible significance of the results and observations are discussed. We are deeply grateful to Dame Janet Vaughan, who very kindly read this manuscript and made several valuable suggestions and criticisms. We are much obliged to Dr Sylvia Fitton-Jackson for her advice on the techniques of tissue culture and for giving us the composition of her chemically defined medium. Dr Palfrey kindly allowed one of us, M. J. Dickens, to learn transmission electron microscopy in his department at St Thomas's Hospital Medical School under the expert tuition of Mr G. Maxwell. Mr R. Hockhan and Mr M. Hepburn of the University of Surrey Structural Studies Unit helpfully instructed in the operation of the transmission electron microscope. Our special thanks are due to Mr E. P. Morris for his competent and enthusiastic technical assistance

Aims

Non-coding microRNA (miRNA) in extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) may promote neuronal repair after spinal cord injury (SCI). In this paper we report on the effects of MSC-EV-microRNA-381 (miR-381) in a rodent model of SCI.

Aims

This study aimed to determine if macrophages can attach and directly affect the oxide layers of 316L stainless steel, titanium alloy (Ti6Al4V), and cobalt-chromium-molybdenum alloy (CoCrMo) by releasing components of these alloys.

Aims

Ageing-related incompetence becomes a major hurdle for the clinical translation of adult stem cells in the treatment of osteoarthritis (OA). This study aims to investigate the effect of stepwise preconditioning on cellular behaviours in human mesenchymal stem cells (hMSCs) from ageing patients, and to verify their therapeutic effect in an OA animal model.

Lesions within the articular cartilage layer of synovial joints do not heal spontaneously. Some repair cells may appear, but their failure to become established may be related to problems of adhesion to proteoglycan-rich surfaces. We therefore investigated whether controlled enzymatic degradation of surface proteoglycan molecules to a depth of about 1 μm, using chondroitinase ABC, would improve coverage by repair cells. We created superficial lesions (1.0 × 0.2 × 5 mm) in the articular cartilage of mature rabbit knees and treated the surfaces with 1 U/ml of chondroitinase ABC for four minutes. The defects were studied by histomorphometry and electron microscopy at one, three and six months. At one month, untreated lesions were covered to a mean extent of 28% by repair cells; this was enhanced to a mean of 53% after enzyme treatment. By three months, the mean coverage of both control and chondroitinase-ABC-treated defects had diminished dramatically to 0.2% and 13%, respectively, but at six months both untreated and treated lesions had a similar coverage of about 30%, not significantly different from that achieved in untreated knees at one month. These findings suggest that, with time, chondrocytes near the surface of the defect may compensate for the loss of proteoglycans produced by enzyme treatment, thereby restoring the inhibitory properties of the matrix as regards cell adhesion. This supposition was confirmed by electron microscopy. Our results have an important bearing on attempts made to induce healing responses by transplanting chondrogenic cells or by applying growth factors

Aims

Bone metastasis ultimately occurs due to a complex multistep process, during which the interactions between cancer cells and bone microenvironment play important roles. Prior to colonization of the bone, cancer cells must succeed through a series of steps that will allow them to gain migratory and invasive properties; epithelial-to-mesenchymal transition (EMT) is known to be integral here. The aim of this study was to determine the effects of G protein subunit alpha Q (GNAQ) on the mechanisms underlying bone metastasis through EMT pathway.

Aims

Rheumatoid arthritis (RA), which mainly results from fibroblast-like synoviocyte (FLS) dysfunction, is related to oxidative stress. Advanced oxidation protein products (AOPPs), which are proinflammatory mediators and a novel biomarker of oxidative stress, have been observed to accumulate significantly in the serum of RA patients. Here, we present the first investigation of the effects of AOPPs on RA-FLSs and the signalling pathway involved in AOPP-induced inflammatory responses and invasive behaviour.

1. The surface of mature adult human articular cartilage from the knee has been studied by electron microscopy in eleven patients ranging in age from thirty-seven to eighty-three years. The ultrastructural appearance varies from person to person and often from area to area in the same specimen. These variations range from an intact surface to one showing overt fibrillation visible with the light microscope. 2. In areas where the articular surface appears intact the underlying superficial matrix consists of closely packed collagen fibres with only a small amount of interfibrillary ground substance. The collagen fibres show a predominantly tangential orientation in this region of the cartilage. Osmophilic lipidic bodies are sometimes seen in the matrix very close to the joint surface. 3. The appearances under the electron microscope are altered in what is interpreted as an early ultrastructural change in the development of cartilage fibrillation. In the affected areas the collagen fibres show abnormally wide separation by an excessive amount of interfibrillary matrix. Collagen fibres become directly exposed to the joint cavity, and the surface can also show accumulations of finely granular material and sometimes tuft-like projections containing collagen fibres and fine fibrils. At a slightly later stage shallow clefts and steeply sloping curves are apparent at the surface. It is suggested that these various alterations precede the development of overt fibrillation visible under the light microscope. 4. Electron micrographs occasionally show small "blisters" at the articular surface. Electron microscopy has not given evidence of shedding of cells into the joint cavity from non-fibrillated areas of adult human articular cartilage. Cells can, however, sometimes become exposed at the surface in fibrillated areas

Aims

The aim of this study was to determine the extent to which patient demographics, clinical presentation, and blood parameters vary in Kingella kingae septic arthritis when compared with those of other organisms, and whether this difference needs to be considered when assessing children in whom a diagnosis of septic arthritis is suspected.

Aims

LY3023414 is a novel oral phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) dual inhibitor designed for advanced cancers, for which a phase II clinical study was completed in March 2020; however, little is known about its effect on bone modelling/remodelling. In this study, we aimed to explore the function of LY3023414 in bone modelling/remodelling.