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Elkington RJ, Hall RM, Beadling AR, Pandit H, Bryant MG. Highly lubricious SPMK-g-PEEK implant surfaces to facilitate rehydration of articular cartilage. J Mech Behav Biomed Mater 2023; 147:106084. [PMID: 37683556 DOI: 10.1016/j.jmbbm.2023.106084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 08/16/2023] [Accepted: 08/20/2023] [Indexed: 09/10/2023]
Abstract
To enable long lasting osteochondral defect repairs which preserve the native function of synovial joint counter-face, it is essential to develop surfaces which are optimised to support healthy cartilage function by providing a hydrated, low friction and compliant sliding interface. PEEK surfaces were modified using a biocompatible 3-sulfopropyl methacrylate potassium salt (SPMK) through UV photo-polymerisation, resulting in a ∼350 nm thick hydrophilic coating rich in hydrophilic anionic sulfonic acid groups. Characterisation was done through Fourier Transformed Infrared Spectroscopy, Focused Ion Beam Scanning Electron Microscopy, and Water Contact Angle measurements. Using a Bruker UMT TriboLab, bovine cartilage sliding tests were conducted with real-time strain and shear force measurements, comparing untreated PEEK, SPMK functionalised PEEK (SPMK-g-PEEK), and Cobalt Chrome Molybdenum alloy. Tribological tests over 2.5 h at physiological loads (0.75 MPa) revealed that SPMK-g-PEEK maintains low friction (μ< 0.024) and minimises equilibrium strain, significantly reducing forces on the cartilage interface. Post-test analysis showed no notable damage to the cartilage interfacing against the SPMK functionalised surfaces. The application of a constitutive biphasic cartilage model to the experimental strain data reveals that SPMK surfaces increase the interfacial permeability of cartilage in sliding, facilitating fluid and strain recovery. Unlike previous demonstrations of sliding-induced tribological rehydration requiring specific hydrodynamic conditions, the SPMK-g-PEEK introduces a novel mode of tribological rehydration operating at low speeds and in a stationary contact area. SPMK-g-PEEK surfaces provide an enhanced cartilage counter-surface, which provides a highly hydrated and lubricious boundary layer along with supporting biphasic lubrication. Soft polymer surface functionalisation of orthopaedic implant surfaces are a promising approach for minimally invasive synovial joint repair with an enhanced bioinspired polyelectrolyte interface for sliding against cartilage. These hydrophilic surface coatings offer an enabling technology for the next generation of focal cartilage repair and hemiarthroplasty implant surfaces.
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Affiliation(s)
- Robert J Elkington
- Institute of Functional Surfaces, Mechanical Engineering, University of Leeds, Leeds, LS2 9JT, Yorkshire, UK.
| | - Richard M Hall
- Institute of Thermofluids, Mechanical Engineering, University of Leeds, Leeds, LS2 9JT, Yorkshire, UK
| | - Andrew R Beadling
- Institute of Functional Surfaces, Mechanical Engineering, University of Leeds, Leeds, LS2 9JT, Yorkshire, UK
| | - Hemant Pandit
- Leeds Institute of Rheumatic and Musculoskeletal Medicine, Chapel Allerton Hospital, Chapeltown Road, Leeds, LS7 4SA, Yorkshire, UK
| | - Michael G Bryant
- Institute of Functional Surfaces, Mechanical Engineering, University of Leeds, Leeds, LS2 9JT, Yorkshire, UK
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Holy CE, Zhang S, Perkins LE, Hasgall P, Katz LB, Brown JR, Orlandini L, Fessel G, Nasseri-Aghbosh B, Eichenbaum G, Egnot NS, Marcello S, Coplan PM. Site-specific cancer risk following cobalt exposure via orthopedic implants or in occupational settings: A systematic review and meta-analysis. Regul Toxicol Pharmacol 2021; 129:105096. [PMID: 34896478 DOI: 10.1016/j.yrtph.2021.105096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 11/30/2021] [Accepted: 12/02/2021] [Indexed: 10/19/2022]
Abstract
In 2020, the European Commission up-classified metal cobalt as Class 1B Carcinogen (presumed to have carcinogenic potential) based primarily on data from rodent inhalation carcinogenicity studies. This up-classification requires an assessment under the Medical Device Regulations of cobalt cancer risk from medical devices. We performed a systematic review and meta-analysis to evaluate site-specific cancer risks with cobalt exposure from either total joint replacement (TJR) or occupational exposure (OC). Results were stratified by exposure type (OC or TJR), exposure level (metal-on-metal (MoM) or non-MoM), follow-up duration (latency period: <5, 5-10 or >10 years), and cancer incidence or mortality (detection bias assessment). From 30 studies (653,104 subjects, average 14.5 years follow-up), the association between TJR/OC and cancer risk was null for 22 of 27 cancer sites, negative for 3 sites, and positive for prostate cancer and myeloma. Significant heterogeneity and large estimate ranges were observed for many cancer sites. No significant increase in estimates was observed by exposure level or follow-up duration. The current evidence, including weak associations, heterogeneity across studies and no increased association with exposure level or follow-up duration, is insufficient to conclude that there exists an increased risk for people exposed to cobalt in TJR/OC of developing site-specific cancers.
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Affiliation(s)
- Chantal E Holy
- Johnson & Johnson, 410 George St, New Brunswick, NJ, 08901, United States.
| | - Shumin Zhang
- Johnson & Johnson, 410 George St, New Brunswick, NJ, 08901, United States
| | - Laura E Perkins
- Abbott Vascular, 3200 Lakeside Dr, Santa Clara, CA, 95054, United States
| | | | - Laurence B Katz
- LifeScan Global Corporation, 20 Valley Stream Parkway, Malvern, PA, 19355, United States
| | - Jason R Brown
- Medtronic PLC, 8200 Coral Sea St NE, Minneapolis, MN, 55112, United States
| | - Luca Orlandini
- Smith and Nephew, Oberneuhofstasse 10D, 6340, Baar, Switzerland
| | - Gion Fessel
- Smith and Nephew, Oberneuhofstasse 10D, 6340, Baar, Switzerland
| | | | - Gary Eichenbaum
- Johnson & Johnson, 410 George St, New Brunswick, NJ, 08901, United States
| | - Natalie S Egnot
- Cardno ChemRisk, 20 Stanwix St, Pittsburgh, PA, 15222, United States
| | | | - Paul M Coplan
- Johnson & Johnson, 410 George St, New Brunswick, NJ, 08901, United States; University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, 19104, United States
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