Proteoglycan 4 reduces friction more than other synovial fluid components for both cartilage-cartilage and cartilage-metal articulation

Abstract

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Friction reducing ability of a poly‐l‐lysine and dopamine modified hyaluronan coating for polycaprolactone cartilage resurfacing implants

“…37 A previous study using the same setup showed that CoF values using the present lubricant solution were close to values obtained with bovine synovial fluid for a cartilage-on-cartilage interface. 4 It is known that synovial fluid components and concentrations can change during the progression of osteoarthritis. 8,37 Future research should determine the effect of altered concentrations of lubricant components and the addition of phospholipids on the lubricating ability of the PLL-HADN coating.…”

“…1,2 Previous research has shown that the mucin-like glycoprotein, proteoglycan 4 (PRG4) also known as lubricin, plays an important friction-reducing role in this mechanism. [3][4][5][6][7][8][9] In contrast to fluid-film lubrication, not only the composition of the lubricant is of importance, but also the biochemical properties, macromolecular composition and structure of the articulating surfaces. 10,11 When focal cartilage defects are treated with artificial biomaterials, the natural lubrication mechanism is disturbed.…”

“…12 Previous in vitro studies have shown that these types of materials exhibit suboptimal surface properties and generally lack sufficient lubrication, which can lead to tissue degradation and decreased lifespan post-implantation in vivo. 4,[13][14][15][16][17][18][19] Surface modifications like coatings are often used to enhance lubrication of synthetic systems. Also for medical devices, including orthopedic implants, coatings can be used to improve lubrication and wear resistance.…”

“…28,31 Previous studies have shown that the mucin domains of PRG4 are able to reduce friction between two opposing (synthetic) articulating layers. 4,5,7 Therefore, the present study specifically focusses on in whether PRG4 binds to this LbL PLL-HADN coating.…”

Ultrasound-Based Quantification of Cartilage Damage After In Vivo Articulation With Metal Implants

“… 13 Furthermore, animal studies have repeatedly shown that metal FKRIs cause damage to the opposing cartilage. 6 - 8 , 11 , 16 While this damage is most likely a result of the mismatch between the mechanical properties of cartilage and the implant, most notably their stiffness, other factors such as the coefficient of friction between metal and cartilage—reported to be up to 10 times higher between CoCr and cartilage than between cartilage and cartilage 19 - 21 —and inaccurate implant positioning may also play a role. 7 While considerable cartilage damage may occur in the cartilage opposing a metal implant irrespective of placement depth, the damage is significantly less when the implant is placed flush with the surrounding cartilage than when it is recessed or protruding.…”