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Metal detectors have been present in airports and points of departure for some time. With the introduction of heightened security measures in response to fears of an increased threat of terrorism, they may become more prevalent in other public locations. The aim of this study was to ascertain which prosthetic devices activated metal detector devices used for security purposes. A range of prosthetic devices used commonly in orthopaedic and plastic surgery procedures were passed through an arch metal detector at Birmingham Airport in the UK. Additionally, each item was passed under a wand detector. Items tested included expandable breast prostheses, plates used in wrist and hand surgery, screws, K-wires, Autosuture™ ligation clips and staples. No prostheses were detected by the arch detector. The expandable implants and wrist plates were the only devices detected by passing the wand directly over them. No device was detected by the wand when it was under cover of the axillary soft tissue. Screws, K-wires, Autosuture™ clips and staples were not detected under any of the study conditions. Although unlikely to trigger a detector, it is possible that an expandable breast prosthesis or larger plate may do so. It is therefore best to warn patients of this so they can anticipate detection and further examination.

Introduction of metals as biomaterials has been known for a long time. In the early development, sufficient strength and suitable mechanical properties were the main considerations for metal implants. With the development of new generations of biomaterials, the concepts of bioactive and biodegradable materials were proposed. Biological function design is very import for metal implants in biomedical applications. Three crucial design criteria are summarized for developing metal implants: (1) mechanical properties that mimic the host tissues; (2) sufficient bioactivities to form bio-bonding between implants and surrounding tissues; and (3) a degradation rate that matches tissue regeneration and biodegradability. This article reviews the development of metal implants and their applications in biomedical engineering. Development trends and future perspectives of metallic biomaterials are also discussed.

Metal implants are commonly used in clinical practice. However, little is known regarding the prevalence of metal implants. Therefore, this study aimed to evaluate the prevalence of metal implants in the United States (US) among individuals aged ≥ 40 years. This study conducted a serial cross-sectional analysis of US adults aged ≥ 40 years who participated in the National Health and Nutrition Examination Survey (NHANES) (2015–2016 and 2017–March 2020). Self-reported questionnaires were used to assess whether the participants had metal implants inside their bodies. The primary outcome was the prevalence of metal implants among adults aged 40 years and older. Furthermore, weighted logistic regression analysis was employed to determine the changes in the prevalence of metal implants from 2015 to March 2020. Moreover, this study investigated the variation in metal implant prevalence by demographic factors based on the pooled NHANES cycles. All analyses were conducted based on 3,736 participants from the NHANES 2015–2016 and 6,387 participants from the NHANES 2017–March 2020. This study observed a high prevalence of metal implants among adults aged 40 and older (2015–2016: 27.23%; 2017–March 2020: 31.53%). Moreover, the results of the weighted logistic regression analysis showed that the prevalence of metal implants significantly increased from 2015 to March 2020, especially among older individuals, men, and White individuals. In addition, the results of the weighted logistic regression analysis indicated that the metal implant prevalence differed by age and race/ethnicity, in which older individuals and White individuals showed a significantly higher prevalence of metal implants than younger individuals and non-White individuals, respectively. There was a high prevalence of metal implants among US adults aged 40 and older, and the prevalence of metal implants significantly increased from 2015 to March 2020. Therefore, more attention needs to be paid to this special population, and it may be necessary to ensure accessibility and affordability and assess the potential long-term health impacts of metal implants, considering the increased prevalence of metal implants.

Purpose Surgical treatment options for the management of focal chondral and osteochondral lesions in the knee include biological solutions and focal metal implants. A treatment gap exists for patients with lesions not suitable for arthroplasty or biologic repair or who have failed prior cartilage repair surgery. This study reports on the early clinical and functional outcomes in patients undergoing treatment with an individualised mini-metal implant for an isolated focal chondral defect in the knee. Methods Open-label, multicentre, non-randomised, non-comparative retrospective observational analysis of prospectively collected clinical data in a consecutive series of 80 patients undergoing knee reconstruction with the Episealer® implant. Knee injury and Osteoarthritis Outcome Score (KOOS) and VAS scores, were recorded preoperatively and at 3 months, 1 year, and 2 years postoperatively. Results Seventy-five patients were evaluated at a minimum 24 months following implantation. Two patients had undergone revision (2.5%), 1 declined participation, and 2 had not completed the full data requirements, leaving 75 of the 80 with complete data for analysis. All 5 KOOS domain mean scores were significantly improved at 1 and 2 years ( p  < 0.001–0.002). Mean preoperative aggregated KOOS4 of 35 (95% CI 33.5–37.5) improved to 57 (95% CI 54.5–60.2) and 59 (95% CI 55.7–61.6) at 12 and 24 months respectively ( p  < 0.05). Mean VAS score improved from 63 (95% CI 56.0–68.1) preoperatively to 32 (95% CI 24.4–38.3) at 24 months. The improvement exceeded the minimal clinically important difference (MCID) and this improvement was maintained over time. Location of defect and history of previous cartilage repair did not significantly affect the outcome ( p  > 0.05). Conclusion The study suggests that at 2 years, Episealer® implants are safe with a low failure rate of 2.5% and result in clinically significant improvement. Individualised mini-metal implants with appropriate accurate guides for implantation appear to have a place in the management of focal femoral chondral and osteochondral defects in the knee. Level of evidence IV.

Background Metal-on-metal implants are a special form of hip endoprostheses that despite many advantages can entail serious complications due to release of wear particles from the implanted material. Metal wear particles presumably activate local host defence mechanisms, which causes a persistent inflammatory response with destruction of bone followed by a loosening of the implant. To better characterize this inflammatory response and to link inflammation to bone degradation, the local generation of proinflammatory and osteoclast-inducing cytokines was analysed, as was systemic T cell activation. Methods By quantitative RT-PCR, gene expression of cytokines and markers for T lymphocytes, monocytes/macrophages and osteoclasts, respectively, was analysed in tissue samples obtained intraoperatively during exchange surgery of the loosened implant. Peripheral T cells were characterized by cytofluorometry before surgery and 7 to 10 days thereafter. Results At sites of osteolysis, gene expression of cathepsin K, CD14 and CD3 was seen, indicating the generation of osteoclasts, and the presence of monocytes and of T cells, respectively. Also cytokines were highly expressed, including CXCL8, IL-1ß, CXCL2, MRP-14 and CXCL-10. The latter suggest T cell activation, a notion that could be confirmed by detecting a small, though conspicuous population of activated CD4+ cells in the peripheral blood T cells prior to surgery. Conclusion Our data support the concept that metallosis is the result of a local inflammatory response, which according to histomorphology and the composition of the cellular infiltrate classifies as an acute phase of a chronic inflammatory disease. The proinflammatory environment, particularly the generation of the osteoclast-inducing cytokines CXCL8 and IL1-ß, promotes bone resorption. Loss of bone results in implant loosening, which then causes the major symptoms of metallosis, pain and reduced range of motion.

Background We evaluated whether 16-bit CT reconstruction with explicit CT-to-electron-density (CT-to-ED) calibration improves dose-calculation accuracy versus conventional 12-bit reconstruction in the presence of metallic implants, and whether geometric metrics can identify cases that benefit most. Methods CT-to-ED tables were built for both bit depths. In Solid Water, dose profiles and absolute dose were compared against EBT4 film and TG-51 ion-chamber measurements. Eight clinical IMRT plans were optimized and cross-recalculated between bit-depth domains with segments and monitor units fixed. A beam–metal interaction metric, η metal (monitor-unit–weighted beam’s-eye-view overlap), and the volumetric overlap ratio (VOR) between metal and PTV were computed. Gamma passing rate (GPR, 3 mm/3%), mean gamma, profile error, and absolute-dose deviation were evaluated. Results In the phantom, 16-bit improved agreement over 12-bit, yielding higher GPR, profile differences ≤ 2%, and absolute-dose errors ≤ 1.0%; 12-bit showed profile errors up to 5.4% (stainless steel) and 3.0% (titanium) and absolute-dose errors of 2.3% and 1.7%. In patients, η metal  > 35% was associated with GPR < 90% when 12-bit plans were recalculated on 16-bit, whereas low η metal maintained ≥ 90%. η metal correlated positively with VOR and negatively with GPR, supporting pre-treatment triage via VOR. Conclusions Extended-bit reconstruction mitigates HU saturation, improves RED assignment, and yields better agreement with measurements and calculation. These findings support adopting 16-bit CT with CT-to-ED calibration as the default for planning and verification in patients with metallic implants, with VOR or η metal flagging cases where benefit is greatest.

Purpose To compare the advantages and disadvantages of biodegradable and non-degradable implants in orthopedic fractures. Methods Recent original articles about biodegradable and non-degradable implants for fracture fixation were reviewed extensively, and a comprehensive retrospective analysis was performed. Results Standard orthopedic treatment is to use non-degradable metal implants to fixate the fracture site. This kind of treatment not only causes rejection and stress shielding, but also requires a second surgery to remove the metal implants. In addition, this kind of treatment increases physical pain and is a serious financial burden to patients. However, biodegradable implants do not require a second surgery for removal and have good biocompatibility and osteoconductivity. Conclusions Biodegradable implants do not require a second surgery for removal and have good biocompatibility and osteoconductivity. Consequently, they are an ideal treatment and are increasingly used for orthopedic surgical patients. The most common indications for biodegradable implants include craniofacial reconstruction, anterior cruciate ligament reconstruction, meniscus repair, ankle fracture treatment, and tibia and fibula fracture treatment.

In this work, the micro-arc oxidation method is used to fabricate surface-modified complex-structured titanium implant coatings to improve biocompatibility. Depending on the utilized electrolyte solution and micro-arc oxidation process parameters, three different types of coatings (one of them—oxide, another two—calcium phosphates) were obtained, differing in their coating thickness, crystallite phase composition and, thus, with a significantly different biocompatibility. An analytical approach based on X-ray computed tomography utilizing software-aided coating recognition is employed in this work to reveal their structural uniformity. Electrochemical studies prove that the coatings exhibit varying levels of corrosion protection. In vitro and in vivo experiments of the three different micro-arc oxidation coatings prove high biocompatibility towards adult stem cells (investigation of cell adhesion, proliferation and osteogenic differentiation), as well as in vivo biocompatibility (including histological analysis). These results demonstrate superior biological properties compared to unmodified titanium surfaces. The ratio of calcium and phosphorus in coatings, as well as their phase composition, have a great influence on the biological response of the coatings.

Background Every year, hundreds of thousands of patients receive an orthopaedic or dental implant containing metals such as cobalt, chromium and titanium. Since the European Chemicals Agency (2020) classified pure cobalt metal as a Category 1B carcinogen, manufacturers of products containing ≥ 0.1% of this metal must perform a risk assessment and justify that there are no viable alternatives. The up-classification of cobalt metal to a carcinogen without good evidence that its use in implants is carcinogenic may cause unnecessary concern to the many patients who have, or may require such implants. Although in vitro and animal studies have shown such metals to be carcinogenic, human epidemiological studies have not been definitive. In addition, although many advances have been made in the past few decades with regard to the materials used in implant metals, no recent review of their carcinogenic effects have been published. Methods This scoping review aims to summarise epidemiological studies conducted in recent years (from 2010 to present) to outline the carcinogenic effects of orthopaedic metal implants that have been published. This encompasses implants of different materials and surfaces, including metal, polyethylene and ceramic orthopaedic implants, cemented and cementless joint replacement surgeries, and surgical techniques such as resurfacing and total joint replacements that are currently in use and the potential carcinogenicity related to their use. Research papers with various study designs published in the English language were included. Studies were excluded if participants had a prior history of cancer before receiving orthopaedic implants and if they focused solely on the carcinogenicity of metals or materials not related to orthopaedic implants. Results A total of 16 studies, encompassing over 700,000 implant patients, were identified through PubMed and have been included in this review. In long term follow-up of up to 17.9 years, no increased risk of all-site cancer was seen in these patients. However, an increase in site-specific cancers, namely prostate, melanoma and haematological cancers have been identified. Specifically, an increase in prostate cancer was identified in three studies. Conclusion Based on the summarised evidence, there is no consistent evidence to show that patients with any type of orthopaedic implant has an increased risk of cancer, although slight (non-statistically significant) increases in prostate cancer was observed and this, in particular, deserves longer-term surveillance.

Purpose: Surgical treatment options for the management of focal chondral and osteochondral lesions in the knee include biological solutions and focal metal implants. A treatment gap exists for patients with lesions not suitable for arthroplasty or biologic repair or who have failed prior cartilage repair surgery. This study reports on the early clinical and functional outcomes in patients undergoing treatment with an individualised mini-metal implant for an isolated focal chondral defect in the knee. Methods: Open-label, multicentre, non-randomised, non-comparative retrospective observational analysis of prospectively collected clinical data in a consecutive series of 80 patients undergoing knee reconstruction with the Episealer® implant. Knee injury and Osteoarthritis Outcome Score (KOOS) and VAS scores, were recorded preoperatively and at 3months, 1year, and 2years postoperatively. Results: Seventy-five patients were evaluated at a minimum 24months following implantation. Two patients had undergone revision (2.5%), 1 declined participation, and 2 had not completed the full data requirements, leaving 75 of the 80 with complete data for analysis. All 5 KOOS domain mean scores were significantly improved at 1 and 2years (p < 0.001–0.002). Mean preoperative aggregated KOOS4 of 35 (95% CI 33.5–37.5) improved to 57 (95% CI 54.5–60.2) and 59 (95% CI 55.7–61.6) at 12 and 24months respectively (p < 0.05). Mean VAS score improved from 63 (95% CI 56.0–68.1) preoperatively to 32 (95% CI 24.4–38.3) at 24months. The improvement exceeded the minimal clinically important difference (MCID) and this improvement was maintained over time. Location of defect and history of previous cartilage repair did not significantly affect the outcome (p > 0.05). Conclusion: The study suggests that at 2years, Episealer® implants are safe with a low failure rate of 2.5% and result in clinically significant improvement. Individualised mini-metal implants with appropriate accurate guides for implantation appear to have a place in the management of focal femoral chondral and osteochondral defects in the knee. Level of evidence: IV. © 2020, The Author(s).