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Medicolegal Sidebar: Nuclear Verdicts-Should Orthopaedic Surgeons Be Concerned? Clin Orthop Relat Res 2024; 482:773-775. [PMID: 38536109 PMCID: PMC11008655 DOI: 10.1097/corr.0000000000003049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Accepted: 02/28/2024] [Indexed: 04/13/2024]
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Medicolegal Sidebar: The End May Be Near for Noncompete Agreements. Clin Orthop Relat Res 2023; 481:2321-2324. [PMID: 37889593 PMCID: PMC10642887 DOI: 10.1097/corr.0000000000002912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 10/05/2023] [Indexed: 10/29/2023]
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Medicolegal Sidebar: Free Speech Rights Versus Off-Label Use. Clin Orthop Relat Res 2023; 481:1285-1287. [PMID: 37229553 PMCID: PMC10263206 DOI: 10.1097/corr.0000000000002719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 05/08/2023] [Indexed: 05/27/2023]
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Medicolegal Sidebar: Healthcare Fraud and Abuse Laws-Illustrative Case of an Indicted Surgeon. Clin Orthop Relat Res 2022; 480:2298-2301. [PMID: 36239610 PMCID: PMC10550021 DOI: 10.1097/corr.0000000000002432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 09/08/2022] [Indexed: 11/22/2022]
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Medicolegal Sidebar: Are Implant Sales Reps in the Operating Room Legally Untouchable? Clin Orthop Relat Res 2022; 480:669-671. [PMID: 35195552 PMCID: PMC8923589 DOI: 10.1097/corr.0000000000002157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 02/07/2022] [Indexed: 01/31/2023]
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Transforaminal lumbar interbody fusion with a silicon nitride cage demonstrates early radiographic fusion. JOURNAL OF SPINE SURGERY (HONG KONG) 2022; 8:29-43. [PMID: 35441113 PMCID: PMC8990392 DOI: 10.21037/jss-21-115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 01/14/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND Degeneration of the lumbar spine is common in aging adults and reflects a significant morbidity burden in this population. In selected patients that prove unresponsive to non-surgical treatment, posterior lumbar fusion (PLF) surgery, with or without adjunctive transforaminal lumbar interbody fusion (TLIF) can relieve pain and improve function. We describe here the radiographic fusion rates for PLF versus TLIF, using an intervertebral spinal cage made of silicon nitride ceramic (chemical formula Si3N4). METHODS This retrospective cohort analysis enrolled 99 patients from August 2013 to January 2017; 17 had undergone PLF at 24 levels, while 82 had undergone TLIF at 104 levels. All operations were performed by a single surgeon at one institution. Radiographic and clinical outcomes were compared between PLF and TLIF at 2 and 6 weeks and then at 3, 6, 12, and 24 months. RESULTS TLIF patients fused at higher rates compared to PLF at the 3-month (38.5% vs. 8.3%, P=0.006), 6-month (78.7% vs. 35.0%, P<0.001) and 12-month time periods (97.9% vs. 81.3%, P=0.018), with no difference at 24 months (100% vs. 94.4%, P=0.102). Index level segmental motion was significantly less and intervertebral disc height was improved in TLIF over PLF at all follow up intervals. Foraminal height was only greater in early follow up periods (2 weeks, 6 weeks and 3 months). TLIF patients experienced lover rates of PI-LL mismatch which was maintained across long term follow-up. Pelvic tilt was lower following TLIF compared to PLF, with no differences in complication rates between study groups. CONCLUSIONS Our retrospective series demonstrated that TLIF performed with silicon nitride interbody cages led to earlier radiographic fusion, greater restoration of disc and foraminal height, increased segmental rigidity and improved sagittal alignment when compared to PLF alone.
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Medicolegal Sidebar: A Fast Route To A Criminal Indictment-Violating Fraud and Abuse Laws. Clin Orthop Relat Res 2021; 479:2362-2365. [PMID: 34402805 PMCID: PMC8509973 DOI: 10.1097/corr.0000000000001943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 07/20/2021] [Indexed: 01/31/2023]
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Medicolegal Sidebar: Telemedicine-New Opportunities and New Risks. Clin Orthop Relat Res 2021; 479:1671-1673. [PMID: 34100792 PMCID: PMC8277285 DOI: 10.1097/corr.0000000000001856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 05/19/2021] [Indexed: 01/31/2023]
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Antifungal activity of polymethyl methacrylate/Si 3N 4 composites against Candida albicans. Acta Biomater 2021; 126:259-276. [PMID: 33727194 DOI: 10.1016/j.actbio.2021.03.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 03/09/2021] [Accepted: 03/09/2021] [Indexed: 12/16/2022]
Abstract
Previous studies using gram-positive and -negative bacteria demonstrated that hydrolysis of silicon nitride (Si3N4) in aqueous suspensions elutes nitrogen and produces gaseous ammonia while buffering pH. According to immunochemistry assays, fluorescence imaging, and in situ Raman spectroscopy, we demonstrate here that the antipathogenic surface chemistry of Si3N4 can be extended to polymethylmethacrylate (PMMA) by compounding it with a minor fraction (~8 vol.%) of Si3N4 particles without any tangible loss in bulk properties. The hydrolytic products, which were eluted from partly exposed Si3N4 particles at the composite surface, exhibited fungicidal action against Candida albicans. Using a specific nitrative stress sensing dye and highly resolved fluorescence micrographs, we observed in situ congestion of peroxynitrite (ONOO-) radicals in the mitochondria of the Candida cells exposed to the PMMA/Si3N4 composite, while these radicals were absent in the mitochondria of identical cells exposed to monolithic PMMA. These in situ observations suggest that the surface chemistry of Si3N4 mimics the antifungal activity of macrophages, which concurrently produce NO radicals and superoxide anions (O2•-) resulting in the formation of candidacidal ONOO-. The fungicidal properties of PMMA/Si3N4 composites could be used in dental appliances to inhibit the uncontrolled growth of Candida albicans and ensuing candidiasis while being synergic with chemoprophylaxis. STATEMENT OF SIGNIFICANCE: In a follow-up of previous studies of gram-positive and gram-negative bacteria, we demonstrate here that the antipathogenic surface chemistry of Si3N4 could be extended to polymethylmethacrylate (PMMA) containing a minor fraction (~8 vol.%) of Si3N4 particles without tangible loss in bulk properties. Hydrolytic products eluted from Si3N4 particles at the composite surface exhibited fungicidal action against Candida albicans. Highly resolved fluorescence microscopy revealed congestion of peroxynitrite (ONOO-) radicals in the mitochondria of the Candida cells exposed to the PMMA/Si3N4 composite, while radicals were absent in the mitochondria of identical cells exposed to monolithic PMMA. The fungicidal properties of PMMA/Si3N4 composites could be used in dental appliances to inhibit uncontrolled growth of Candida albicans and ensuing candidiasis in synergy with chemoprophylaxis.
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Surface functionalization of PEEK with silicon nitride. Biomed Mater 2020; 16. [PMID: 32906100 DOI: 10.1088/1748-605x/abb6b1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 09/09/2020] [Indexed: 12/18/2022]
Abstract
Surface roughness, bioactivity, and antibacterial properties are desirable in skeletal implants. We hot-pressed a mix of particulate sodium chloride (NaCl) salt and silicon nitride (β-Si3N4) onto the surface of bulk PEEK. NaCl grains were removed by leaching in water, resulting in a porous PEEK surface embedded with ~15 vol.% β-Si3N4 particles. This functionalized surface showed the osteogenic and antibacterial properties previously reported in bulk silicon nitride implants. Surface enhancement of PEEK with β-Si3N4 could improve the performance of spinal fusion cages, by facilitating arthrodesis and resisting bacteria.
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Two-year results of a double-blind multicenter randomized controlled non-inferiority trial of polyetheretherketone (PEEK) versus silicon nitride spinal fusion cages in patients with symptomatic degenerative lumbar disc disorders. JOURNAL OF SPINE SURGERY 2020; 6:523-540. [PMID: 33102889 DOI: 10.21037/jss-20-588] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Background During lumbar spinal fusion, spacer cages are implanted to provide vertebral stability, restore sagittal alignment, and maintain disc and foraminal height. Polyetheretherketone (PEEK) is commonly used by most spine surgeons. Silicon nitride (Si3N4) is a less well-known alternative although it was first used as a spacer in lumbar fusion over 30 years ago. The present study was designed to see if Si3N4 cages would perform similarly to PEEK in a randomized controlled trial. Methods A non-inferiority multicenter 100-patient study was designed where both the observer and patient were blinded. Single- or double-level transforaminal lumbar interbody fusion with pedicle screw fixation using an oblique PEEK or Si3N4 cage was performed. The primary non-inferiority outcome was the Roland-Morris Disability Questionnaire (RMDQ). Secondary measures included the Oswestry Disability Questionnaire, Visual Analogue Scales (VAS) for back and leg pain, SF-36 Physical and Mental Function indices, patient and surgeon Likert scores on perceived recovery, and X-ray and CT radiological evaluations for subsidence, segmental motion, and fusion. Follow-up evaluations occurred at 3, 6, 12, and 24 months. Results After exclusions for protocol violations and canceled surgeries, 92 patients were randomized (i.e., 48 for PEEK and 44 for Si3N4). There were no differences in baseline demographics, pre-operative disabilities, or pain scores between the groups. Both treatment arms showed significant improvements in disability, pain, and recovery scores. No significant differences were observed for subsidence, segmental motion, or fusion. For the primary outcome (i.e., RMDQ scores), the non-inferiority of Si3N4 compared to PEEK could not be established using the original protocol criteria. However, the comparison was undermined by larger than anticipated patient fallout coupled with higher than expected RMDQ score standard deviations. A post hoc analysis coupled with a more extensive review of the literature was conducted which resulted in the selection of a revised clinically justified non-inferiority margin; and using this method, the non-inferiority of Si3N4 was affirmed. Conclusions This study demonstrated that the use of either PEEK or Si3N4 cages is safe and effective for patients undergoing lumbar spine fusion for chronic degenerative disc disease.
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Clinical outcomes for lumbar fusion using silicon nitride versus other biomaterials. JOURNAL OF SPINE SURGERY (HONG KONG) 2020; 6:33-48. [PMID: 32309644 PMCID: PMC7154368 DOI: 10.21037/jss.2019.12.11] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 11/12/2019] [Indexed: 12/18/2022]
Abstract
BACKGROUND In lumbar fusion surgery, intervertebral spacer cages made of silicon nitride (Si3N4) ceramic are an available option among other biomaterials. While the surface chemistry of Si3N4 is known to favor bone fusion, large-scale clinical studies attesting to its efficacy are lacking. This multicenter retrospective study compared lumbar fusion outcomes for Si3N4 cages to previously reported data for other cage materials. METHODS Pre-operative patient demographics, comorbidities, changes in visual analog scale (ΔVAS) pain scores, complications, adverse events, and secondary surgical interventions (SSI) were compiled from the records of 450 patients who underwent Si3N4 lumbar spinal fusion at four separate U.S. surgical centers. For comparison, MEDLINE/PubMed and Google Scholar searches identified studies reporting similar outcomes for other biomaterials. A total of 1,025 patients from 26 cohorts reported in 14 publications met inclusion criteria for this control group. RESULTS Overall, the mean last-follow-up for all patients was 341±293 days (11.4±9.8 months), with the longest follow-up being 6.4 years. Patients with Si3N4 implants were similar in gender and age distribution to the control group but had higher BMI values (30.9±6.1 vs. 25.8±4.1, P<0.01) and lower tobacco use (15.8% vs. 30.0%, P<0.01). Both the Si3N4 and control groups showed significant improvements in VAS pain scores from preoperative to last follow-up. For the Si3N4 group, ΔVAS was 36.8±35.4 points compared to 37.6±22.5 points (P=0.63) for the metadata group. Complications and reoperations for the Si3N4 and the control groups were similar (i.e., 9.8% and 3.1% versus 12.4% and 2.9%, P=0.16 and P=0.84, respectively). CONCLUSIONS Lumbar fusion with Si3N4 spacers compared favorably with the improvements reported with other commonly used biomaterial cages.
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Clinical outcomes for anterior cervical discectomy and fusion with silicon nitride spine cages: a multicenter study. JOURNAL OF SPINE SURGERY (HONG KONG) 2019; 5:504-519. [PMID: 32043001 PMCID: PMC6989924 DOI: 10.21037/jss.2019.11.17] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 11/12/2019] [Indexed: 11/06/2022]
Abstract
BACKGROUND Intervertebral spacers made of silicon nitride (Si3N4) are currently used in cervical and thoracolumbar fusion. While basic science data demonstrate several advantages of Si3N4 over other biomaterials, large-scale clinical results on its safety and efficacy are lacking. This multicenter retrospective study examined outcomes for anterior cervical discectomy and fusion (ACDF) using Si3N4 cages. Results were compared to compiled metadata for other ACDF materials. METHODS Pre-operative patient demographics, comorbidities, changes in visual analog scale (VAS) pain scores, complications, adverse events, and secondary surgical interventions were collected from the medical records of 860 patients who underwent Si3N4 ACDF at four surgical centers. For comparison, MEDLINE/PubMed and Google Scholar searches were performed for ACDF using other cage or spacer materials. Nine studies with 13 cohorts and 736 patients met the inclusion criteria for this control group. RESULTS Overall, the mean last-follow-up for all patients was 319±325 days (10.6±10.8 months), with the longest follow-up being 6.5 years. In comparison to the metadata, patients from the Si3N4 groups were older (57.9±12.2 vs. 56.8±11.1 y, P=0.06) and had higher BMI values (30.0±6.3 vs. 28.1±6.5, P<0.01), but gender and smoking were not different. The Si3N4 patients reported significant improvements in VAS pain scores at last follow-up (i.e., pre-op of 71.0±22.1 vs. follow-up of 36.4±31.5, P<0.01). Although both preoperative and last-follow-up pain scores were higher for Si3N4 patients than the control, the overall change in scores (ΔVAS) was similar. From pre-op to last-follow up, ΔVAS values were 35.4±34.3 for patients receiving the Si3N4 implants versus 34.4±27.3 for patients from the meta-analysis (P=0.56). The complication and reoperation rate for the Si3N4 and the metadata were also comparable (i.e., 7.39% and 0.31% versus 9.79% and 0%, P=0.17 and 0.25, respectively). CONCLUSIONS ACDF outcomes using Si3N4 implants matched the clinical efficacy of other cage biomaterials.
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3D-additive deposition of an antibacterial and osteogenic silicon nitride coating on orthopaedic titanium substrate. J Mech Behav Biomed Mater 2019; 103:103557. [PMID: 32090951 DOI: 10.1016/j.jmbbm.2019.103557] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 11/07/2019] [Accepted: 11/25/2019] [Indexed: 12/29/2022]
Abstract
A 3D-additive manufacturing approach produced a dense Si3N4 ceramic coating on a biomedical grade commercially pure titanium (cp-Ti) substrate by an automatic laser-sintering procedure. Si3N4 coatings could be prepared with thicknesses from the single to the tens of microns. A coating thickness, t = 15 ± 5 μm, was selected for this study, based on projections of homogeneity and scratching resistance. The Si3N4 coating met the 20 N threshold required for biomaterial applications, according to the standard scratch testing (ASTM C1624-05). The Si3N4 coating imparted both the antibacterial and osteogenic properties of bulk Si3N4 to the cp-Ti substrate. Both properties were comparable to those previously described for bulk Si3N4 biomedical implants. The newly developed Si3N4-coating was applied to commercially available Ti-alloy acetabular shells for total hip arthroplasty. A "glowing" test based on luciferase gene transformation was applied to visualize the colonization of gram-negative Escherichia coli on Si3N4-coated and uncoated Ti-alloy acetabular shells. The results showed that the coating technology conferred resistance to Staphylococcus epidermidis and Escherichia coli adhesion onto the bulk acetabular sockets.
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Enhanced bioactivity of Si 3N 4 through trench-patterning and back-filling with Bioglass®. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2019; 106:110278. [PMID: 31753392 DOI: 10.1016/j.msec.2019.110278] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 09/18/2019] [Accepted: 10/05/2019] [Indexed: 11/18/2022]
Abstract
Using a simple and innovative sandblasting process, disks of monolithic biomedical silicon nitride (β-Si3N4) were texturized with a matrix of regular, discrete square trenches with a total depth in the range of hundreds of microns. The process consisted of sandblasting Si3N4 substrates through a stainless-steel wire-mesh (150 or 200 μm) using abrasive silicon carbide powders (α-SiC, ∼40 μm) under 1,034 kPa (150 psi) of gas pressure. The depth of the porosities could be controlled varying both the treatment time and the distance from the surface. Part of the samples were then filled with 45S5 Bioglass® powders to improve the osteointegration and stimulate the production of bone tissue. Due to the increased macroscopic and microscopic roughness, biological testing using human osteosarcoma cells (SaOS-2) showed improved cell proliferation and greater production of both mineral (hydroxyapatite) and organic (collagen) phases on the patterned surfaces compared to untreated β-Si3N4 or to the biomedical titanium control samples. Both of these effects were further enhanced when the porosities were filled with Bioglass®.
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Off-Stoichiometric Reactions at the Cell-Substrate Biomolecular Interface of Biomaterials: In Situ and Ex Situ Monitoring of Cell Proliferation, Differentiation, and Bone Tissue Formation. Int J Mol Sci 2019; 20:E4080. [PMID: 31438530 PMCID: PMC6751500 DOI: 10.3390/ijms20174080] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 08/15/2019] [Accepted: 08/17/2019] [Indexed: 11/18/2022] Open
Abstract
The availability of osteoinductive biomaterials has encouraged new therapies in bone regeneration and has potentially triggered paradigmatic shifts in the development of new implants in orthopedics and dentistry. Among several available synthetic biomaterials, bioceramics have gained attention for their ability to induce mesenchymal cell differentiation and successive bone formation when implanted in the human body. However, there is currently a lack of understanding regarding the fundamental biochemical mechanisms by which these materials can induce bone formation. Phenomenological studies of retrievals have clarified the final effect of bone formation, but have left the chemical interactions at the cell-material interface uncharted. Accordingly, the knowledge of the intrinsic material properties relevant for osteoblastogenesis and osteoinduction remains incomplete. Here, we systematically monitored in vitro the chemistry of mesenchymal cell metabolism and the ionic exchanges during osteoblastogenesis on selected substrates through conventional biological assays as well as via in situ and ex situ spectroscopic techniques. Accordingly, the chemical behavior of different bioceramic substrates during their interactions with mesenchymal cells could be unfolded and compared with that of biomedical titanium alloy. Our goal was to clarify the cascade of chemical equations behind the biological processes that govern osteoblastogenic effects on different biomaterial substrates.
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Patients, pictures, and privacy: managing clinical photographs in the smartphone era. Arthroplast Today 2019; 5:57-60. [PMID: 31020023 PMCID: PMC6470317 DOI: 10.1016/j.artd.2018.10.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 10/01/2018] [Accepted: 10/02/2018] [Indexed: 11/27/2022] Open
Abstract
It is easy to capture and share clinical photographs and x-ray images using modern smartphones. This technology affords health-care providers the ability to rapidly collaborate and facilitate care for their patients. This improvement, however, has increased concerns regarding patient privacy and the safeguarding of protected health information. Health-care providers should understand the deidentification process for patient photographs because this process fundamentally changes the expectations and requirements for how providers are to handle this information. Properly deidentified patient photographs (and other data) are no longer considered identifiable protected health information and are not subject to the handling requirements mandated by the Health Insurance Portability and Accountability Act. This article addresses patient privacy concerns attendant to the acquisition, transmission, and sharing of clinical photographs among health-care providers. It provides guidelines for providers seeking to minimize the risk of noncompliance with privacy requirements as they adopt these new technologies into their practices.
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Bioglass functionalization of laser-patterned bioceramic surfaces and their enhanced bioactivity. Heliyon 2018; 4:e01016. [PMID: 30560211 PMCID: PMC6288463 DOI: 10.1016/j.heliyon.2018.e01016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Revised: 11/05/2018] [Accepted: 12/04/2018] [Indexed: 11/29/2022] Open
Abstract
The surfaces of silicon nitride (β-Si3N4) and zirconia toughened alumina (ZTA) were patterned using a high-energy laser source, which operated at a wavelength of 1064 nm. The patterning procedure yielded a series regular, cylindrical cavities 500 and 300 μm in diameter and depth, respectively. These cavities were subsequently filled with bioglass mixed with different fractions of Si3N4 powder (0, 5, and 10 mol.%) to obtain bioactive functionalized bioceramic surfaces. The laser-patterned samples were first characterized using several spectroscopic techniques before and after functionalization, and then tested in vitro with respect to their osteoconductivity using a human osteosarcoma cell line (SaOS-2). After in vitro testing, fluorescence microscopy was used to address the biological response and to estimate osteopontin and osteocalcin protein contents and distributions. The presence of bioglass greatly enhanced the biological response of both ceramic surfaces, but mainly induced production of inorganic apatite. On the other hand, the addition of minor fraction of Si3N4 into the bioglass-filled holes greatly enhanced bio-mineralization and stimulated the SaOS-2 cells to produce higher amounts of bone extracellular matrix (collagen and proteins), thus enhancing the osteopontin to osteocalcin ratio. It was also observed that the presence of a fraction of Si3N4 in the powder mixture filling the holes bestowed more uniform cell colonization on the otherwise bioinert ZTA surface.
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Medicolegal Sidebar: Who Should Obtain Informed Consent? Clin Orthop Relat Res 2018; 476:1566-1568. [PMID: 29846202 PMCID: PMC6259771 DOI: 10.1097/corr.0000000000000351] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 04/25/2018] [Indexed: 01/31/2023]
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A single center retrospective clinical evaluation of anterior cervical discectomy and fusion comparing allograft spacers to silicon nitride cages. JOURNAL OF SPINE SURGERY (HONG KONG) 2018; 4:349-360. [PMID: 30069528 PMCID: PMC6046334 DOI: 10.21037/jss.2018.06.02] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 05/25/2018] [Indexed: 04/27/2023]
Abstract
BACKGROUND Iliac crest autograft or allograft spacers have been traditionally utilized in anterior cervical discectomy and fusion (ACDF) to provide vertebral stabilization and enhanced osteogenesis. However, abiotic cages have largely replaced these allogenic sources due to host-site morbidities and disease transmission risks, respectively. Although devices made of polyetheretherketone (PEEK) or titanium-alloys (Ti) have gained wide popularity, they lack osteoinductive or conductive capabilities. In contrast, silicon nitride (Si3N4) is a relatively new implant material that also provides structural stability and yet purportedly offers osteopromotive and antimicrobial behavior. This study compared radiographic outcomes at ≥12 months of follow-up for osseous integration, fusion rate, time to fusion, and subsidence in ACDF patients with differing intervertebral spacers. METHODS Fifty-eight ACDF patients (108 segments) implanted with Si3N4 cages were compared to thirty-four similar ACDF patients (61 segments) implanted with fibular allograft spacers. Lateral radiographs (normal, flexion, and extension) were obtained at 3, 6, 12, and 24 months to assess osseous integration, the presence of bridging bone, the absence of peri-implant radiolucencies, subsidence, and fusion using both interspinous distance (ISD) and Cobb angle methods. RESULTS In patients with ≥12 months of follow-up, fusion for the allograft spacers and Si3N4 cages was 86.84% and 96.83%, respectively (ISD method, P=0.10), and 67.65% and 84.13%, respectively (Cobb angle method P=0.07), while osseointegration was 76.32% and 93.65%, respectively (P=0.02). The time to fusion significantly favored the Si3N4 cages (4.08 vs. 8.64 months (ISD method, P=0.01), and 6.76 vs. 11.74 months (Cobb angle method, P=0.04). The assessed time for full osseointegration was 7.83 and 19.24 months for Si3N4 and allograft, respectively (P=0.00). Average subsidence at 1-year follow-up was 0.51 and 2.71 mm for the Si3N4 and allograft cohorts, respectively (P=0.00). CONCLUSIONS In comparison to fibular allograft spacers, Si3N4 cages showed earlier osseointegration and fusion, higher fusion rates, and less subsidence.
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Incorporating Si3
N4
into PEEK to Produce Antibacterial, Osteocondutive, and Radiolucent Spinal Implants. Macromol Biosci 2018; 18:e1800033. [DOI: 10.1002/mabi.201800033] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/15/2018] [Indexed: 11/09/2022]
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Oxide ceramic femoral heads contribute to the oxidation of polyethylene liners in artificial hip joints. J Mech Behav Biomed Mater 2018; 82:168-182. [PMID: 29601988 DOI: 10.1016/j.jmbbm.2018.03.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/12/2018] [Accepted: 03/15/2018] [Indexed: 12/01/2022]
Abstract
Experimental evidence demonstrates that a loss of stoichiometry at the surface of oxide bioceramic femoral heads enhances the oxidation rate of polyethylene acetabular liners in artificial hip joints. Contradicting the common notion that ceramics are bioinert, three independent experiments confirmed substantial chemical interactions between the ceramic femoral heads and their polyethylene counterparts. The experiments reported herein included hydrothermal tests, frictional tests, and hip-simulator experiments. It was discovered that oxide and non-oxide femoral heads differently affected the oxidation processes at the surface of the polyethylene liners, all other testing parameters being equal. Analytical data from X-ray photoelectron (XPS), cathodoluminescence (CL), Fourier-transform infrared (FTIR), and Raman spectroscopies unequivocally and consistently showed that the oxidation rate of polyethylene liners was greater when coupled with oxide as opposed to non-oxide ceramic heads. XPS analyses of O-Al-O bond fractions at the surface of a zirconia-toughened alumina (ZTA) short-term (20 months in vivo) femoral heads retrieval showed a ~50% reduction in favor of oxygen vacancy O-Al-VO and hydroxylated Al-O-H bonds. Off-stoichiometry drifts were confirmed in vitro under both static and dynamic conditions. They triggered oxidation and tangibly affected an advanced highly cross-linked sequentially irradiated and annealed ultra-high molecular weight polyethylene (UHMWPE) liner (increase in oxidation index up to ΔOI~1.2 after 5 × 105 cycles under dynamic swing conditions). Second-generation UHMWPE liners infused with vitamin E were also affected by the free flow of oxygen from the oxide femoral heads, although to a lesser extent. The fundamental findings of this study, which were also confirmed on retrievals, call for revised standards in material design and testing. Adopting these new criteria will provide an improved understanding of the importance of off-stoichiometry at the head/liner interface and may lead to significant extensions in artificial joint lifetimes.
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Mobile Messaging Communication in Health Care: Rules, Regulations, Penalties, and Safety of Provider Use. JBJS Rev 2018; 6:e4. [PMID: 29557794 DOI: 10.2106/jbjs.rvw.17.00070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Overuse of Magnetic Resonance Imaging in the Diagnosis and Treatment of Moderate to Severe Osteoarthritis. THE IOWA ORTHOPAEDIC JOURNAL 2018; 38:33-37. [PMID: 30104922 PMCID: PMC6047403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
BACKGROUND MRI in the evaluation of end-stage knee joint osteoarthritis (OA) is usually unnecessary when radiographic and clinical evidence of gonarthrosis is clear. The purpose of this study was to assess the prevalence of MRI scans ordered in patients with radiographically obvious gonarthrosis and to examine the characteristics of health care providers who ordered these imaging studies. METHODS We retrospectively identified 164 patients diagnosed with moderate to severe OA who were referred for total knee replacement (TKA) over a one-year period. The percentage of patients who had an MRI scan with or without X-ray, within the preceding 3 months prior to referral, were calculated. Subgroups were analyzed to identify characteristics that may influence the decision to order an MRI, including K-L grade, provider type, level of training, and practice location. RESULTS Of 145 patients, 19 (13.1%) presented with an MRI scan. Between the number of MRI scans ordered, there was a significant difference when comparing physicians versus non-physicians, with physicians ordering less MRI scans (p=0.018). There was a significant difference when comparing non-academic versus academic, with academic providers ordering less MRI scans (p=0.044). There was no significant difference with fellowship training or provider proximity to our academic institution. CONCLUSIONS In this study, 13.1% of patients with radiographically obvious knee OA obtained an MRI prior to referral for TKA. Non-physicians and non-academic physicians were more likely to order MRI scans. Improved education for referring providers may be necessary to decrease overuse of MRI in the diagnosis of moderate to severe arthritis. LEVEL OF EVIDENCE Level II.
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In vitroantibacterial activity of oxide and non-oxide bioceramics for arthroplastic devices: II. Fourier transform infrared spectroscopy. Analyst 2018; 143:2128-2140. [DOI: 10.1039/c8an00234g] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The metabolic response of Gram-positiveStaphylococcus epidermidisbacteria to bioceramic substrates was probed by Fourier transform infrared spectroscopy.
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Human osteoblasts grow transitional Si/N apatite in quickly osteointegrated Si 3N 4 cervical insert. Acta Biomater 2017; 64:411-420. [PMID: 28963015 DOI: 10.1016/j.actbio.2017.09.038] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 09/25/2017] [Accepted: 09/25/2017] [Indexed: 11/24/2022]
Abstract
Silicon nitride (Si3N4) ceramics possesses surface chemistry that accelerates bone repair, as previously established by in vitro experiments using both osteosarcoma and mesenchymal cells. The release of silicic acid and nitrogen compounds from the surface Si3N4 enhanced in vitro cellular activity. The results of this study demonstrate for the first time that the osseointegration behavior previously observed is operative with a peculiar chemistry within the human milieu. Si and N elements stimulated progenitor cell differentiation and osteoblastic activity, which ultimately resulted in accelerated bone ingrowth. At the molecular scale, insight into the effect of silicon and nitrogen ions released from the Si3N4 surface was obtained through combined histomorphometric analyses, Raman, Fourier-transform-infrared, and X-ray photoelectron spectroscopies. Identical analyses conducted on a polyetheretherketone (PEEK) spinal explant showed no chemical changes and a lower propensity for osteogenic activity. Silicon and nitrogen are key elements in stimulating cells to generate bony apatite with crystallographic imperfections, leading to enhanced bioactivity of Si3N4 biomedical devices. STATEMENT OF SIGNIFICANCE This research studies osseointegration processes comparing results from explanted PEEK and Si3N4 spinal spacers. Data show that the formation of hydroxyapatite on silicon nitride bio-ceramic surfaces happens with a peculiar mechanism inside the human body. Silicon and nitrogen were incorporated inside the bony tissue structure allowing the developing of off-stoichiometric bony apatite and stimulating progenitor cell differentiation/osteoblastic activity. Silicon and nitrogen ions released from the Si3N4 surface were detected through combined histologic analyses, Raman microspectroscopy, Fourier-transform-infrared, and X-ray photoelectron spectroscopies.
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Medicolegal Sidebar: (Mis)Informed Consent in Medical Negligence Lawsuits. Clin Orthop Relat Res 2017; 475:2643-2646. [PMID: 28884238 PMCID: PMC5638762 DOI: 10.1007/s11999-017-5493-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 08/30/2017] [Indexed: 01/31/2023]
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Surface topography of silicon nitride affects antimicrobial and osseointegrative properties of tibial implants in a murine model. J Biomed Mater Res A 2017; 105:3413-3421. [PMID: 28865177 DOI: 10.1002/jbm.a.36189] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 07/10/2017] [Accepted: 08/16/2017] [Indexed: 12/28/2022]
Abstract
While silicon nitride (Si3 N4 ) is an antimicrobial and osseointegrative orthopaedic biomaterial, the contribution of surface topography to these properties is unknown. Using a methicillin-resistant strain of Staphylococcus aureus (MRSA), this study evaluated Si3 N4 implants in vitro utilizing scanning electron microscopy (SEM) with colony forming unit (CFU) assays, and later in an established in vivo murine tibia model of implant-associated osteomyelitis. In vitro, the "as-fired" Si3 N4 implants displayed significant reductions in adherent bacteria versus machined Si3 N4 (2.6 × 104 vs. 8.7 × 104 CFU, respectively; p < 0.0002). Moreover, SEM imaging demonstrated that MRSA cannot directly adhere to native as-fired Si3 N4 . Subsequently, a cross-sectional study was completed in which sterile or MRSA contaminated as-fired and machined Si3 N4 implants were inserted into the tibiae of 8-week old female Balb/c mice, and harvested on day 1, 3, 5, 7, 10, or 14 post-operatively for SEM. The findings demonstrated that the antimicrobial activity of the as-fired implants resulted from macrophage clearance of the bacteria during biofilm formation on day 1, followed by osseointegration through the apparent recruitment of mesenchymal stem cells on days 3-5, which differentiated into osteoblasts on days 7-14. In contrast, the antimicrobial behavior of the machined Si3 N4 was due to repulsion of the bacteria, a phenomenon that also limited osteogenesis, as host cells were also unable to adhere to the machined surface. Taken together, these results suggest that the in vivo biological behavior of Si3 N4 orthopaedic implants is driven by critical features of their surface nanotopography. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3413-3421, 2017.
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Medicolegal Sidebar: Resident Physician Liability. Clin Orthop Relat Res 2017; 475:1963-1965. [PMID: 28597148 PMCID: PMC5498399 DOI: 10.1007/s11999-017-5402-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 05/31/2017] [Indexed: 01/31/2023]
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Tough and strong porous bioactive glass-PLA composites for structural bone repair. JOURNAL OF MATERIALS SCIENCE 2017; 52:9039-9054. [PMID: 28943655 PMCID: PMC5606147 DOI: 10.1007/s10853-017-0777-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 01/09/2017] [Indexed: 06/07/2023]
Abstract
Bioactive glass scaffolds have been used to heal small contained bone defects but their application to repairing structural bone is limited by concerns about their mechanical reliability. In the present study, the addition of an adherent polymer layer to the external surface of strong porous bioactive glass (13-93) scaffolds was investigated to improve their toughness. Finite element modeling (FEM) of the flexural mechanical response of beams composed of a porous glass and an adherent polymer layer predicted a reduction in the tensile stress in the glass with increasing thickness and elastic modulus of the polymer layer. Mechanical testing of composites with structures similar to the models, formed from 13-93 glass and polylactic acid (PLA), showed trends predicted by the FEM simulations but the observed effects were considerably more dramatic. A PLA layer of thickness -400 µm, equal to -12.5% of the scaffold thickness, increased the load-bearing capacity of the scaffold in four-point bending by ~50%. The work of fracture increased by more than 10,000%, resulting in a non-brittle mechanical response. These bioactive glass-PLA composites, combining bioactivity, high strength, high work of fracture and an internal architecture shown to be conducive to bone infiltration, could provide optimal implants for healing structural bone defects.
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Development of a SiYAlON glaze for improved osteoconductivity of implantable medical devices. J Biomed Mater Res B Appl Biomater 2017; 106:1084-1096. [PMID: 28503805 DOI: 10.1002/jbm.b.33914] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 04/11/2017] [Accepted: 04/22/2017] [Indexed: 12/20/2022]
Abstract
The application of bioactive coatings onto orthopaedic appliances is commonly performed to compensate for the otherwise bioinert nature of medical devices and to improve their osseointegration. Calcium phosphates, hydroxyapatite (HAp), and bioglasses are commercially available for this purpose. Until recently, few other inorganic compounds have been identified with similar biofunctionality. However, silicon nitride (Si3 N4 ) has emerged as a new orthopaedic material whose unique surface chemistry also enhances osteoconductivity. Recent research has confirmed that its minority intergranular phase, consisting of silicon yttrium aluminum oxynitride (SiYAlON), is principally responsible for this improvement. As a result, it was hypothesized that SiYAlON itself might serve as an effective osteoconductive coating or glaze for medical devices. To test this hypothesis, a process inspired by traditional ceramic whiteware glazing was developed. A slurry containing ingredients similar to the intergranular SiYAlON composition was applied to a Si3 N4 surface, which was then subjected to a heat treatment to form a glaze. Various analytical tools were employed to assess its chemistry and morphology. It was found that the glaze was comprised predominately of Y5 Si3 O12 N, a compound commonly referred to as N-apatite, which is isostructural to native HAp. Subsequent exposure of the glazed surface to acellular simulated body fluid led to increased deposition of biomimetic HAp-like crystals, while exposure to Saos-2 osteosarcoma cells in vitro resulted in greater HAp deposition relative to control samples. The observation that SiYAlON exhibits enhanced osteoconductivity portends its potential as a therapeutic aid in bone and tissue repair. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1084-1096, 2018.
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Medicolegal Sidebar: Expanding Hospital Liability-The Concept of Willful Blindness. Clin Orthop Relat Res 2017; 475:1315-1318. [PMID: 28229326 PMCID: PMC5384936 DOI: 10.1007/s11999-017-5282-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 02/06/2017] [Indexed: 01/31/2023]
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Bacteriostatic behavior of surface modulated silicon nitride in comparison to polyetheretherketone and titanium. J Biomed Mater Res A 2017; 105:1521-1534. [PMID: 28000413 DOI: 10.1002/jbm.a.35987] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 11/23/2016] [Accepted: 12/15/2016] [Indexed: 01/23/2023]
Abstract
Perioperative and latent infections are leading causes of revision surgery for orthopaedic devices resulting in significant increased patient care, comorbidities, and attendant costs. Identifying biomaterial surfaces that inherently resist biofilm adhesion and bacterial expression is an important emerging strategy in addressing implant-related infections. This in vitro study was designed to compare biofilm formation on three biomaterials commonly employed in spinal fusion surgery-silicon nitride (Si3 N4 ), polyetheretherketone (PEEK), and a titanium alloy (Ti6Al4V-ELI) -using one gram-positive and one gram-negative bacterial species. Disc samples from various surface treated Si3 N4 , PEEK, and Ti6Al4V were inoculated with 105 CFU/mm2 Staphylococcus epidermidis (ATCC®14990™) or Escherichia coli (ATCC® 25922™) and cultured in PBS, 7% glucose, and 10% human plasma for 24 and 48 h, followed by retrieval and rinsing. Vortexed solutions were diluted, plated, and incubated at 37 °C for 24 to 48 h. Colony forming units (CFU/mm2 ) were determined using applicable dilution factors and surface areas. A two-tailed, heteroscedastic Student's t-test (95% confidence) was used to determine statistical significance. The various Si3 N4 samples showed the most favorable bacterial resistance for both bacilli tested. The mechanisms for the bacteriostatic behavior of Si3 N4 are likely due to multivariate surface effects including submicron-topography, negative charging, and chemical interactions which form peroxynitrite (an oxidative agent). Si3 N4 is a new biomaterial with the apparent potential to inhibit biofilm formation. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1521-1534, 2017.
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Reconciling in vivo and in vitro kinetics of the polymorphic transformation in zirconia-toughened alumina for hip joints: I. Phenomenology. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2017; 72:252-258. [DOI: 10.1016/j.msec.2016.11.059] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 10/18/2016] [Accepted: 11/16/2016] [Indexed: 02/04/2023]
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Reconciling in vivo and in vitro kinetics of the polymorphic transformation in zirconia-toughened alumina for hip joints: II. Theory. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2017; 71:446-451. [DOI: 10.1016/j.msec.2016.10.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 09/05/2016] [Accepted: 10/16/2016] [Indexed: 11/28/2022]
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Reconciling in vivo and in vitro kinetics of the polymorphic transformation in zirconia-toughened alumina for hip joints: III. Molecular scale mechanisms. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2017; 71:552-557. [DOI: 10.1016/j.msec.2016.11.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 09/05/2016] [Accepted: 11/02/2016] [Indexed: 11/25/2022]
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The Law and Social Values: Medical Uncertainty. Clin Orthop Relat Res 2017; 475:27-30. [PMID: 27785673 PMCID: PMC5174062 DOI: 10.1007/s11999-016-5127-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 10/11/2016] [Indexed: 01/31/2023]
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Wear and surface degradation of commercial ZTA femoral heads under boundary lubrication conditions. J Mech Behav Biomed Mater 2017; 65:616-626. [DOI: 10.1016/j.jmbbm.2016.09.038] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 09/19/2016] [Accepted: 09/28/2016] [Indexed: 11/26/2022]
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On the molecular interaction between femoral heads and polyethylene liners in artificial hip joints: phenomenology and molecular scale phenomena. Biomed Mater 2016; 12:015005. [DOI: 10.1088/1748-605x/12/1/015005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Creation of bioactive glass (13–93) scaffolds for structural bone repair using a combined finite element modeling and rapid prototyping approach. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2016; 68:651-662. [DOI: 10.1016/j.msec.2016.06.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 05/06/2016] [Accepted: 06/04/2016] [Indexed: 10/21/2022]
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Effect of copper-doped silicate 13–93 bioactive glass scaffolds on the response of MC3T3-E1 cells in vitro and on bone regeneration and angiogenesis in rat calvarial defects in vivo. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2016; 67:440-452. [DOI: 10.1016/j.msec.2016.05.073] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 04/15/2016] [Accepted: 05/16/2016] [Indexed: 12/30/2022]
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In Situ Spectroscopic Screening of Osteosarcoma Living Cells on Stoichiometry-Modulated Silicon Nitride Bioceramic Surfaces. ACS Biomater Sci Eng 2016; 2:1121-1134. [DOI: 10.1021/acsbiomaterials.6b00126] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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The Law and Social Values: Medical Necessity and Criminal Prosecution. Clin Orthop Relat Res 2016; 474:887-91. [PMID: 26857621 PMCID: PMC4773337 DOI: 10.1007/s11999-016-4725-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 01/22/2016] [Indexed: 01/31/2023]
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Silicon Nitride Bioceramics Induce Chemically Driven Lysis in Porphyromonas gingivalis. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:3024-35. [PMID: 26948186 DOI: 10.1021/acs.langmuir.6b00393] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Organisms of Gram-negative phylum bacteroidetes, Porphyromonas gingivalis, underwent lysis on polished surfaces of silicon nitride (Si3N4) bioceramics. The antibacterial activity of Si3N4 was mainly the result of chemically driven principles. The lytic activity, although not osmotic in nature, was related to the peculiar pH-dependent surface chemistry of Si3N4. A buffering effect via the formation of ammonium ions (NH4(+)) (and their modifications) was experimentally observed by pH microscopy. Lysis was confirmed by conventional fluorescence spectroscopy, and the bacteria's metabolism was traced with the aid of in situ Raman microprobe spectroscopy. This latter technique revealed the formation of peroxynitrite within the bacterium itself. Degradation of the bacteria's nucleic acid, drastic reduction in phenilalanine, and reduction of lipid concentration were observed due to short-term exposure (6 days) to Si3N4. Altering the surface chemistry of Si3N4 by either chemical etching or thermal oxidation influenced peroxynitrite formation and affected bacteria metabolism in different ways. Exploiting the peculiar surface chemistry of Si3N4 bioceramics could be helpful in counteracting Porphyromonas gingivalis in an alkaline pH environment.
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Preparation of resorbable carbonate-substituted hollow hydroxyapatite microspheres and their evaluation in osseous defects in vivo. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2016; 60:324-332. [PMID: 26706537 PMCID: PMC4691531 DOI: 10.1016/j.msec.2015.11.039] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 10/27/2015] [Accepted: 11/13/2015] [Indexed: 11/16/2022]
Abstract
Hollow hydroxyapatite (HA) microspheres, with a high-surface-area mesoporous shell, can provide a unique bioactive and osteoconductive carrier for proteins to stimulate bone regeneration. However, synthetic HA has a slow resorption rate and a limited ability to remodel into bone. In the present study, hollow HA microspheres with controllable amounts of carbonate substitution (0-12 wt.%) were created using a novel glass conversion route and evaluated in vitro and in vivo. Hollow HA microspheres with ~12 wt.% of carbonate (designated CHA12) showed a higher surface area (236 m(2) g(-1)) than conventional hollow HA microspheres (179 m(2)g(-1)) and a faster degradation rate in a potassium acetate buffer solution. When implanted for 12 weeks in rat calvarial defects, the CHA12 and HA microspheres showed a limited capacity to regenerate bone but the CHA12 microspheres resorbed faster than the HA microspheres. Loading the microspheres with bone morphogenetic protein-2 (BMP2) (1 μg per defect) stimulated bone regeneration and accelerated resorption of the CHA12 microspheres. At 12 weeks, the amount of new bone in the defects implanted with the CHA12 microspheres (73±8%) was significantly higher than the HA microspheres (59±2%) while the amount of residual CHA12 microspheres (7±2% of the total defect area) was significantly lower than the HA microspheres (21±3%). The combination of these carbonate-substituted HA microspheres with clinically safe doses of BMP2 could provide promising implants for healing non-loaded bone defects.
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Abstract
The menisci are integral components within the knee for ensuring optimal joint function. The overall goal of this study was to identify proteomic markers of meniscal disease within synovial fluid samples obtained from control knees versus knees affected with varying degrees of meniscal injury and osteoarthritis. Joint fluid samples were collected before the patient underwent an arthroscopic knee procedure or total knee arthroplasty. Normal controls included patients younger than 30 years with no history of anterior cruciate ligament, posterior cruciate ligament, or meniscal injury. A total of 21 joint fluid aspirates were analyzed using mass spectrometry, and a total of 296 proteins were identified. Among these, 50 proteins were determined to be of interest as potential biomarkers based on initial analysis and known functions in articular metabolism. Further statistical analysis comparing protein concentrations among clinical groups identified 13 proteins with significant differences between at least two of the patient cohorts. These data provide novel information for the investigation of synovial fluid biomarkers and treatment strategies for meniscal pathology.
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Abstract
The meniscus is a complex tissue and is integral to knee joint health and function. Although the meniscus has been studied for years, a relatively large amount of basic science data on meniscal health and disease are unavailable. Genomic and proteomic analyses of meniscal pathology could greatly improve our understanding of etiopathogenesis and the progression of meniscal disease, yet these analyses are lacking in the current literature. Therefore, the objective of this study was to use microarray and proteomic analyses to compare aged-normal and pathologic meniscal tissues. Meniscal tissue was collected from the knees of five patient groups (n = 3/group). Cohorts included patients undergoing meniscectomy with or without articular cartilage pathology, patients undergoing total knee arthroplasty with mild or moderate-severe osteoarthritis, and aged-normal controls from organ donors. Tissue sections were collected from the white/white and white/red zones of posterior medial menisci. Expression levels were compared between pathologic and control menisci to identify genes of interest (at least a ×1.5 fold change in expression levels between two or more groups) using microarray analysis. Proteomics analysis was performed using mass spectrometry to identify proteins of interest (those with possible trends identified between the aged-normal and pathologic groups). The microarray identified 157 genes of interest. Genes were categorized into the following subgroups: (1) synthesis, (2) vascularity, (3) degradation and antidegradation, and (4) signaling pathways. Mass spectrometry identified 173 proteins of interest. Proteins were further divided into the following categories: (1) extracellular matrix (ECM) proteins; (2) proteins associated with vascularity; (3) degradation and antidegradation proteins; (4) cytoskeleton proteins; (5) glycolysis pathway proteins; and (6) signaling proteins. These data provide novel molecular and biochemical information for the investigation of meniscal pathology. Further evaluation of these disease indicators will help researchers develop algorithms for diagnostic, therapeutic, and prognostic strategies related to meniscal disorders.
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