The use of a bioactive bone cement containing apatite-wollastonite glass-ceramic filler and bisphenol-a-glycidyl methacrylate resin for acetabular fixation in total hip arthroplasty

Human exposure to bisphenol A (BPA) through medical-hospital devices: A systematic review

This systematic review explored the literature pertaining to patient exposure to bisphenol A (BPA) through medical-hospital devices. The acronym PICO: Patient (Medical-hospital devices), Intervention/Exposure (Bisphenol A), Comparison (Different grades of exposure) and Outcome (Assessment of exposure levels) was used. The databases used were LILACS, IBECS, MEDLINE, Capes Journal Portal, Food Science Source, FSTA and CINAHL with Full Text from EBSCO, Embase and Scopus by Elsevier, Web of Science and SCIELO. A total of 9747 references were found. After removing duplicate records, 7129 studies remained. After applying exclusion criteria and qualitative analysis, 12 articles remained. Studies have shown associations between the use of medical-hospital devices and patients' exposure to BPA. For chronic renal patients, there was an association between plasma BPA and disease severity. This review identifies that exposure to BPA is increased after the use of medical-hospital devices. More studies that address the clinical outcome of patients exposed to medical-hospital materials containing BPA are needed.

The superior accuracy of a novel method in total hip wear calculations following radiographic measurement

Background

Polyethylene wear is one of the major concerns of orthopedic surgeons. However, there is no standardized calculation method for the wear rate following radiographic measurement. The purpose of this study was to propose a novel method of wear calculation and to compare its accuracy with a representative conventional method.

Methods

Relative position of the center of the femoral head to that of the cup progresses in one direction following arthroplasty surgery because of bedding-in and wear. We predetermined the amount of bedding-in, wear rate, and random error in measuring the head center position in a 2-dimensional plane. We calculated the wear rate using the head center coordinates over a certain number of measurement periods using a representative conventional method and our novel method. The conventional method consisted of transforming vector data into scalars and conducting a least-squares method. The least-squares method was directly applied to each component of the vector in the novel method. We evaluated the accuracy of these methods by comparing the expected value for the wear rate with their predetermined true values.

Results

If the error were limited to being random, the novel method could provide the predetermined wear rate as the calculation result. However, the conventional method could not.

Conclusion

We recommend using the novel method for the wear calculation rather than the conventional method because of its mathematical accuracy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04964-5.

Mechanical Properties and Bioactivity of Polyetheretherketone/Hydroxyapatite/Carbon Fiber Composite Prepared by the Mechanofusion Process

The main obstacles in the melt-processing of hydroxyapatite (HA) and carbon fiber (CF) reinforced polyetheretherketone (PEEK) composite are the high melting temperature of PEEK, poor dispersion of HA nanofillers, and poor processability due to high filler content. In this study, we prepared PEEK/HA/CF ternary composite using two different non-melt blending methods; suspension blending (SUS) in ethanol and mechanofusion process (MF) in dry condition. We compared the mechanical properties and bioactivity of the composite in a spinal cage application in the orthopedic field. Results showed that the PEEK/HA/CF composite made by the MF method exhibited higher flexural and compressive strengths than the composite prepared by the SUS method due to the enhanced dispersibility of HA nanofiller. On the basis of in vitro cell compatibility and cell attachment tests, PEEK/HA/CF composite by mechanofusion process showed an improvement in in vitro bioactivity and osteo-compatibility.

3D printed chitosan-gelatine hydrogel coating on titanium alloy surface as biological fixation interface of artificial joint prosthesis

To improve the fixation of the prosthesis-bone interface and to prevent postoperative infection, a novel antimicrobial hydrogel coating is designed as the biological fixation interface of the artificial joint prosthesis. Antimicrobial chitosan (CS) and gelatine (GT) were used as bioinks to print a CS-GT hydrogel coating with reticulated porous structure on the titanium alloy substrate by 3D printing technology. The experimental results show that the 7CS-10GT hydrogel coating has a macro-grid structure and honeycomb micro-network structure, excellent hydrophilicity (35.64°), high mechanical strength (elastic modulus 0.92 MPa) and high bonding strength (3.36 MPa) with the titanium alloy substrate. In addition, the antimicrobial effect of 7CS-10GT hydrogel against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) is enhanced after immersion in nano‑silver. Moreover, the 7CS-10GT hydrogel displays good cell compatibility and supports proliferation of NIH-3 T3 cells. In summary, the 3D printed CS-GT antimicrobial hydrogel coating provides an ideal microenvironment for cell adhesion and bone growth due to the dual-scale porous network structure, good hydrophilicity and biocompatibility, thus promoting rapid fixation of the bone interface. This technology opens a new possibility for this biological fixation interface in artificial joint replacement.

Mimicking the electrophysiological microenvironment of bone tissue using electroactive materials to promote its regeneration

The process of bone tissue repair and regeneration is complex and requires a variety of physiological signals, including biochemical, electrical and mechanical signals, which collaborate to ensure functional recovery. The inherent piezoelectric properties of bone tissues can convert mechanical stimulation into electrical effects, which play significant roles in bone maturation, remodeling and reconstruction. Electroactive materials, including conductive materials, piezoelectric materials and electret materials, can simulate the physiological and electrical microenvironment of bone tissue, thereby promoting bone regeneration and reconstruction. In this paper, the structures and performances of different types of electroactive materials and their applications in the field of bone repair and regeneration are reviewed, particularly by providing the results from in vivo evaluations using various animal models. Their advantages and disadvantages as bone repair materials are discussed, and the methods for tuning their performances are also described, with the aim of providing an up-to-date account of the proposed topics.

Microtubule destabilization caused by silicate via HDAC6 activation contributes to autophagic dysfunction in bone mesenchymal stem cells

BACKGROUND

Silicon-modified biomaterials have been extensively studied in bone tissue engineering. In recent years, the toxicity of silicon-doped biomaterials has gradually attracted attention but requires further elucidation. This study was designed to explore whether high-dose silicate can induce a cytotoxicity effect in bone mesenchymal stem cells (BMSCs) and the role of autophagy in its cytotoxicity and mechanism.

METHODS

Morphologic changes and cell viability of BMSCs were detected after different doses of silicate exposure. Autophagic proteins (LC3, p62), LC3 turnover assay, and RFP-GFP-LC3 assay were applied to detect the changes of autophagic flux following silicate treatment. Furthermore, to identify the potential mechanism of autophagic dysfunction, we tested the acetyl-α-tubulin protein level and histone deacetylase 6 (HDAC6) activity after high-dose silicate exposure as well as the changes in microtubule and autophagic activity after HDAC6 siRNA was applied.

RESULTS

It was found that a high dose of silicate could induce a decrease in cell viability; LC3-II and p62 simultaneously increased after high-dose silicate exposure. A high concentration of silicate could induce autophagic dysfunction and cause autophagosomes to accumulate via microtubule destabilization. Results showed that acetyl-α-tubulin decreased significantly with high-dose silicate treatment, and inhibition of HDAC6 activity can restore microtubule structure and autophagic flux.

CONCLUSIONS

Microtubule destabilization caused by a high concentration of silicate via HDAC6 activation contributed to autophagic dysfunction in BMSCs, and inhibition of HDAC6 exerted a cytoprotection effect through restoration of the microtubule structure and autophagic flux.