Aims. We present a case series of five patients who had revision surgery following magnetic controlled growing rods (MGCR) for early onset scoliosis. Metallosis was found during revision in four out of five patients and we postulated a mechanism for rod failure based on retrieval analysis. Patients and Methods. Retrieval analysis was performed on the seven explanted rods. The mean duration of MCGR from implantation to revision was 35 months (17 to 46). The mean age at revision was 12 years (7 to 15; four boys, one girl). Results. A total of six out of seven rods had tissue metallosis and pseudo-capsule surrounding the actuator. A total of four out of seven rods were pistoning. There were two rods which were broken. All rods had abrasive circumferential markings. A significant amount of metal debris was found when the actuators were carefully cut open. Analytical electron microscopy demonstrated metal fragments of predominantly titanium with a mean particle size of 3.36 microns (1.31 to 6.61). Conclusion. This study highlights concerns with tissue metallosis in MCGR. We recommend careful follow-up of patients who have received this implant. Cite this article: Bone Joint J 2016;98-B:1662–7

Aims

In metal-on-polyethylene (MoP) total hip arthroplasty (THA), large metal femoral heads have been used to increase stability and reduce the risk of dislocation. The increased size of the femoral head can, however, lead to increased taper corrosion, with the release of metal ions and adverse reactions. The aim of this study was to investigate the relationship between the size of the femoral head and the levels of metal ions in the blood in these patients.

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The primary aim of this study is to assess the survival of the uncemented hydroxyapatite (HA) coated Trident II acetabular component as part of a hybrid total hip arthroplasty (THA) using a cemented Exeter stem. The secondary aims are to assess the complications, joint-specific function, health-related quality of life, and radiological signs of loosening of the acetabular component.

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This study investigated the effects of transcatheter arterial embolization (TAE) on pain, function, and quality of life in people with early-stage symptomatic knee osteoarthritis (OA) compared to a sham procedure.

A heavy infiltrate of foreign-body macrophages is commonly seen in the fibrous membrane which surrounds an aseptically loose cemented implant. This is in response to particles of polymethylmethacrylate (PMMA) bone cement and other biomaterials. We have previously shown that monocytes and macrophages responding to particles of bone cement are capable of differentiating into osteoclastic cells which resorb bone. To determine whether the radio-opaque additives barium sulphate (BaSO. 4. ) and zirconium dioxide (ZrO. 2. ) influence this process, particles of PMMA with and without these agents were added to mouse monocytes and cocultured with osteoblast-like cells on bone slices. Osteoclast differentiation, as shown by the presence of the osteoclast-associated enzyme tartrate-resistant acid phosphatase (TRAP) and lacunar bone resorption, was observed in all cocultures. The addition of PMMA alone to these cocultures caused no increase in TRAP expression or bone resorption relative to control cocultures. Adding PMMA particles containing BaSO. 4. or ZrO. 2. , however, caused an increase in TRAP expression and a highly significant increase in bone resorption. Particles containing BaSO. 4. were associated with 50% more bone resorption than those containing ZrO. 2. . Our results suggest that radio-opaque agents in bone cement may contribute to the bone resorption of aseptic loosening by enhancing macrophage-osteoclast differentiation, and that PMMA containing is BaSO. 4. likely to be associated with more osteolysis than that containing ZrO. 2.

Osteoarthritis (OA) is a chronic degenerative joint disease characterized by progressive cartilage degradation, synovial membrane inflammation, osteophyte formation, and subchondral bone sclerosis. Pathological changes in cartilage and subchondral bone are the main processes in OA. In recent decades, many studies have demonstrated that activin-like kinase 3 (ALK3), a bone morphogenetic protein receptor, is essential for cartilage formation, osteogenesis, and postnatal skeletal development. Although the role of bone morphogenetic protein (BMP) signalling in articular cartilage and bone has been extensively studied, many new discoveries have been made in recent years around ALK3 targets in articular cartilage, subchondral bone, and the interaction between the two, broadening the original knowledge of the relationship between ALK3 and OA. In this review, we focus on the roles of ALK3 in OA, including cartilage and subchondral bone and related cells. It may be helpful to seek more efficient drugs or treatments for OA based on ALK3 signalling in future.

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In this investigation, we administered oxidative stress to nucleus pulposus cells (NPCs), recognized DNA-damage-inducible transcript 4 (DDIT4) as a component in intervertebral disc degeneration (IVDD), and devised a hydrogel capable of conveying small interfering RNA (siRNA) to IVDD.

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Highly cross-linked polyethylene (HXLPE) greatly reduces wear in total hip arthroplasty, compared to conventional polyethylene (CPE). Cross-linking is commonly achieved by irradiation. This study aimed to compare the degree of cross-linking and in vitro wear rates across a cohort of retrieved and unused polyethylene cups/liners from various brands.

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There is a lack of biomaterial-based carriers for the local delivery of rifampicin (RIF), one of the cornerstone second defence antibiotics for bone infections. RIF is also known for causing rapid development of antibiotic resistance when given as monotherapy. This in vitro study evaluated a clinically used biphasic calcium sulphate/hydroxyapatite (CaS/HA) biomaterial as a carrier for dual delivery of RIF with vancomycin (VAN) or gentamicin (GEN).

The interactions between the different cell types in periprosthetic tissue are still unclear. We used a non-contact coculture model to investigate the effects of polymethylmethacrylate (PMMA) particles and human macrophage-derived soluble mediators on fibroblast activation. Macrophages were either exposed or not exposed to phagocytosable PMMA particles, but fibroblasts were not. Increasing numbers of macrophages were tested in cocultures in which the fibroblast cell number was held constant and cultures of macrophages alone were used for comparison of cytokine release. We used the release of interleukin-1 beta (IL-1β), interleukin 6 (IL-6), tumour necrosis factor alpha (TNF-α), lysosomal enzyme and metalloproteinase activity to assess the cultivation of macrophages and fibroblasts. In cocultures, IL-6 release was increased 100-fold for both unchallenged and particle-challenged cultures when compared with macrophage cultures alone. Furthermore, particle-challenged cocultures had threefold higher IL-6 levels than unchallenged cocultures. Release of TNF-α was similar in cocultures and in macrophage cultures. IL-1β release in cocultures was independent of the macrophage-fibroblast ratio. Lysosomal enzyme activity and metalloproteinase activity were increased in cocultures. Our data show that macrophages and fibroblasts in coculture significantly increase the release of IL-6 and to a less degree other inflammatory mediators; particle exposure accentuates this effect. This suggests that macrophage accumulation in fibrous tissue may lead to elevated IL-6 levels that are much higher than those caused by particle activation of macrophages alone. This macrophage-fibroblast interaction represents a novel concept for the initiation and maintenance of the inflammatory process in periprosthetic membranes

Aims

Large acetabular bone defects encountered in revision total hip arthroplasty (THA) are challenging to restore. Metal constructs for structural support are combined with bone graft materials for restoration. Autograft is restricted due to limited volume, and allogenic grafts have downsides including cost, availability, and operative processing. Bone graft substitutes (BGS) are an attractive alternative if they can demonstrate positive remodelling. One potential product is a biphasic injectable mixture (Cerament) that combines a fast-resorbing material (calcium sulphate) with the highly osteoconductive material hydroxyapatite. This study reviews the application of this biomaterial in large acetabular defects.

1. Currently available total replacement hip and knee prostheses were tested in a machine enabling flexion-extension movements to be applied whilst the prostheses were surrounded with Ringer's solution or other liquid and loaded within the physiological range. 2. Prostheses of which both components were made in cobalt-chromium-molybdenum alloy produced visible quantities of alloy particles, whose sizes ranged down to about 0·1 microns, and cobalt and molybdenum ions in solution. 3. No metallic or plastic particles were detected during tests on a hip prosthesis made of stainless steel and high density polyethylene. 4. The frictional moments in cobalt-chromium-molybdenum hip prostheses were higher than in stainless steel-polyethylene hip prostheses, by a factor of at least 2 to 1. 5. It is accepted that the conditions of these tests were probably more severe than in life, but the difference is held to be one of degree and not one of kind. 6. The particulate alloy debris, when injected in massive doses into the muscles of rats, gave an incidence of malignant tumours which was comparable to that already established for pure cobalt powder, whereas particles of several other metals, tested in the same way, gave no tumours. 7. It is argued that the particles which are known to be produced in at least some patients using cobalt-chromium-molybdenum total replacement joint prostheses constitute a risk of tumour formation which is certainly small, possibly negligible, but not accurately calculable at present. 8. The results of these tests, particularly the differences in frictional moment and in the production of particulate debris, suggest a preference for high density polyethylene as one component of a total joint replacement prosthesis

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To analyze the short-term outcome of two types of total wrist arthroplasty (TWA) in terms of wrist function, migration, and periprosthetic bone behaviour.

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A significant reduction in wear at five and ten years was previously reported when comparing Durasul highly cross-linked polyethylene with nitrogen-sterilized Sulene polyethylene in total hip arthroplasty (THA). We investigated whether the improvement observed at the earlier follow-up continued, resulting in decreased osteolysis and revision surgery rates over the second decade.

We present a case in which the growth of an intraosseous cyst arising from the proximal tibiofibular joint appeared to have been increased by polyethylene wear particles from a medial unicompartmental knee replacement. Histological examination of the cyst wall showed a histiocytic response associated with numerous polyethylene wear particles. This case demonstrates that there is a direct communication between the joint cavity and the cyst. Such communication is probably through openings in the articular cartilage large enough to allow the passage of these particles

Symptomatic cobalt toxicity from a failed total hip replacement is a rare but devastating complication. It has been reported following revision of fractured ceramic components, as well as in patients with failed metal-on-metal articulations. Potential clinical findings include fatigue, weakness, hypothyroidism, cardiomyopathy, polycythaemia, visual and hearing impairment, cognitive dysfunction, and neuropathy. We report a case of an otherwise healthy 46-year-old patient, who developed progressively worsening symptoms of cobalt toxicity beginning approximately six months following synovectomy and revision of a fractured ceramic-on-ceramic total hip replacement to a metal-on-polyethylene bearing. The whole blood cobalt levels peaked at 6521 µg/l. The patient died from cobalt-induced cardiomyopathy. Implant retrieval analysis confirmed a loss of 28.3 g mass of the cobalt–chromium femoral head as a result of severe abrasive wear by ceramic particles embedded in the revision polyethylene liner. Autopsy findings were consistent with heavy metal-induced cardiomyopathy. We recommend using new ceramics at revision to minimise the risk of wear-related cobalt toxicity following breakage of ceramic components. Cite this article: Bone Joint J 2013;95-B:31–7

The membranes surrounding seven loose cementless acetabular implants were shown to contain polyethylene particles, birefringent in polarised light. Three of these implants were made of titanium alloy and the membranes around these contained titanium particles as well. There was no metallosis around the four implants made of chromium-cobalt-steel alloy. Both titanium and polyethylene particles caused migration, adherence and phagocytosis of CD11b-positive, peroxidase-negative macrophages. There were no histological signs of activation of the specific immune response; neither interleukin-2 receptor-positive activated T cells nor PCA-1 plasmablasts/plasma cells were present in the tissues. In cases of simple loosening, resident mesenchymal fibroblast-like cells were active. In aggressive granulomatosis, there were many macrophages and multinucleated giant cells but little fibroblast reaction. The clinical relevance of the findings is that the use of cementless prostheses is not a guarantee against adverse tissue reactions

Aims

Total knee arthroplasty (TKA) is a common and safe orthopaedic procedure. Zimmer Biomet's NexGen is the second most popular brand of implant used in the UK. The primary cause of revision after the first year is aseptic loosening. We present our experience of using this implant, with significant concerns around its performance with regards early aseptic loosening of the tibial component.

Extensive osteolysis adjacent to implants is often associated with wear particles of prosthetic material. We have investigated if RANKL, also known as osteoprotegerin ligand, osteoclast differentiation factor or TRANCE, and its natural inhibitor, osteoprotegerin (OPG), may be important in controlling this bone loss. Cells isolated from periprosthetic tissues containing wear particles expressed mRNA encoding for the pro-osteoclastogenic molecules, RANKL, its receptor RANK, monocyte colony-stimulating factor (M-CSF), interleukin (IL)-1β, tumour necrosis factor (TNF)α, IL-6, and soluble IL-6 receptor, as well as OPG. Osteoclasts formed from cells isolated from periprosthetic tissues in the presence and absence of human osteoblastic cells. When osteoclasts formed in the absence of osteoblastic cells, markedly higher levels of RANKL mRNA relative to OPG mRNA were expressed. Particles of prosthetic materials also stimulated human monocytes to express osteoclastogenic molecules in vitro. Our results suggest that ingestion of prosthetic wear particles by macrophages results in expression of osteoclast-differentiating molecules and the stimulation of macrophage differentiation into osteoclasts

Ferrography is a technique for analysing wear by means of the magnetic separation of wear particles. To evaluate its application in human joints, the results of the ferrographic analysis of saline washings of symptomatic human knees were compared with the results of the arthroscopic examination of the same knees. Ferrography was found to be an extremely sensitive monitor of articular erosion, with a resolution far greater than that of arthroscopy. This was particularly apparent with knees suffering from a torn anterior cruciate ligament: arthroscopy detected no damage to the cartilaginous surfaces whereas ferrography detected a substantial level of "microdamage". The spectrum of wear particles showed qualitative and quantitative alterations depending upon the condition of the knee. Ferrography thus holds much promise as a potential differential diagnostic technique of great sensitivity, with particular relevance to the very early changes which precede clinical symptoms. Study of wear particles is also justified by evidence indicating an active role in the pathophysiological progression of arthritis