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Session: Joints
Session starts: Friday 25 January, 13:00
Presentation starts: 14:15
Room: Lecture room 535

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Alicia Damen (Orthopaedic Biomechanics, Dept. of Biomedical Engineering, Eindhoven University of Technology )
René van Donkelaar ()
Keita Ito ()

Abstract:
Cartilage defects often progress into painful osteoarthritis with decreased range of motion and reduced mobility. Current treatments for cartilage defects depend on patient age and are limited to specific lesion sites or sizes. Especially for the middle-aged patient, no satisfying solutions exist. The MimCart InScite/RegMed project aims to develop a functional universal cartilage-resurfacing biomaterial. This implant involves a hydrogel with a strong swelling potential which is restricted by a knitted spacer fabric, thus mimicking the natural behaviour of respectively the proteoglycans and collagen type II in cartilage. Part of this project aims to minimize friction between implant and opposing cartilage, to prevent wear. The present study assesses the friction between the novel constructs and cartilage, and compares this to friction between cartilage and either cartilage or commercially available metal implants as controls. The coefficient of friction (CoF) was measured with a DHR-3 rheometer, expanded with a ring-on-disk accessory. Full thickness cartilage rings and disks were harvested from bovine patellae. Polylactic acid spacer fabric disks were filled with swelling pHEMA hydrogel. A cartilage ring rotated against a disk of either cartilage or implant material, submerged in PBS, FBS or synovial fluid (SF) at 25°C. Normal load was kept constant at 0.1 MPa and the angular velocity increased from 0.001 rad/s to 10 rad/s. CoF of cartilage-on-cartilage was highest in PBS and lowest in SF, agreeing with previous studies. Furthermore, the filled spacer fabric exhibited a CoF against cartilage which was 50 percent lower than CoCrMo against cartilage. Concluding, first measurements of the CoF using an in vitro cartilage-on-cartilage set-up were performed and the data look promising for further development of the implant. Upcoming, options for optimizing the implant surface using durable lubricating coatings will be explored, and the efficacy of such coatings will be demonstrated using the above presented approach.