T A Schmidt1, R L Sah. 1. Department of Bioengineering and Whitaker Institute of Biomedical Engineering, University of California--San Diego, La Jolla, CA 92093, USA.
Abstract
OBJECTIVES: The lubrication of articulating cartilage surfaces in joints occurs through several distinct modes. In the boundary mode of lubrication, load is supported by surface-to-surface contact, a feature that makes this mode particularly important for maintenance of the normally pristine articular surface. A boundary mode of lubrication is indicated by a kinetic friction coefficient being invariant with factors that influence formation of a fluid film, including sliding velocity and axial load. The objectives of this study were to (1) implement and extend an in vitro articular cartilage-on-cartilage lubrication test to elucidate the dependence of the friction properties on sliding velocity, axial load, and time, and establish conditions where a boundary mode of lubrication is dominant, and (2) determine the effects of synovial fluid (SF) on boundary lubrication using this test. METHODS: Fresh bovine osteochondral samples were analyzed in an annulus-on-disk rotational configuration, maintaining apposed articular surfaces in contact, to determine static (mu(static) and mu(static),(N(eq)) and kinetic ([mu(kinetic)] and [mu(kinetic),(N(eq))]) friction coefficients, each normalized to the instantaneous and equilibrium (N(eq)) normal loads, respectively. RESULTS: With increasing pre-sliding durations, mu(static) and mu(static),(N(eq)) were similar, and increased up to 0.43 +/- 0.03 in phosphate buffered saline (PBS) and 0.19 +/- 0.01 in SF, whereas [mu(kinetic)] and [mu(kinetic),(N(eq))] were steady. Over a range of sliding velocities of 0.1-1 mm/s and compression levels of 18% and 24%, [mu(kinetic)] was 0.072 +/- 0.010 in PBS and 0.014 +/- 0.003 in SF, and [mu(kinetic),(N(eq))] was 0.093 +/- 0.005 in PBS and 0.018 +/- 0.002 in SF. CONCLUSIONS: A boundary mode of lubrication was achieved in a cartilage-on-cartilage test configuration. SF functioned as an effective friction-lowering boundary lubricant for native articular cartilage surfaces.
OBJECTIVES: The lubrication of articulating cartilage surfaces in joints occurs through several distinct modes. In the boundary mode of lubrication, load is supported by surface-to-surface contact, a feature that makes this mode particularly important for maintenance of the normally pristine articular surface. A boundary mode of lubrication is indicated by a kinetic friction coefficient being invariant with factors that influence formation of a fluid film, including sliding velocity and axial load. The objectives of this study were to (1) implement and extend an in vitro articular cartilage-on-cartilage lubrication test to elucidate the dependence of the friction properties on sliding velocity, axial load, and time, and establish conditions where a boundary mode of lubrication is dominant, and (2) determine the effects of synovial fluid (SF) on boundary lubrication using this test. METHODS: Fresh bovine osteochondral samples were analyzed in an annulus-on-disk rotational configuration, maintaining apposed articular surfaces in contact, to determine static (mu(static) and mu(static),(N(eq)) and kinetic ([mu(kinetic)] and [mu(kinetic),(N(eq))]) friction coefficients, each normalized to the instantaneous and equilibrium (N(eq)) normal loads, respectively. RESULTS: With increasing pre-sliding durations, mu(static) and mu(static),(N(eq)) were similar, and increased up to 0.43 +/- 0.03 in phosphate buffered saline (PBS) and 0.19 +/- 0.01 in SF, whereas [mu(kinetic)] and [mu(kinetic),(N(eq))] were steady. Over a range of sliding velocities of 0.1-1 mm/s and compression levels of 18% and 24%, [mu(kinetic)] was 0.072 +/- 0.010 in PBS and 0.014 +/- 0.003 in SF, and [mu(kinetic),(N(eq))] was 0.093 +/- 0.005 in PBS and 0.018 +/- 0.002 in SF. CONCLUSIONS: A boundary mode of lubrication was achieved in a cartilage-on-cartilage test configuration. SF functioned as an effective friction-lowering boundary lubricant for native articular cartilage surfaces.
Authors: Benjamin A Lakin; Harsh Patel; Conor Holland; Jonathan D Freedman; Joshua S Shelofsky; Brian D Snyder; Kathryn S Stok; Mark W Grinstaff Journal: J Orthop Res Date: 2016-01-06 Impact factor: 3.494
Authors: Saleem Abubacker; Dragana Ponjevic; Hyun O Ham; Phillip B Messersmith; John R Matyas; Tannin A Schmidt Journal: Connect Tissue Res Date: 2015-12-02 Impact factor: 3.417
Authors: Corinne R Henak; Benjamin J Ellis; Michael D Harris; Andrew E Anderson; Christopher L Peters; Jeffrey A Weiss Journal: J Biomech Date: 2011-07-14 Impact factor: 2.712
Authors: Natalie K Galley; Jason P Gleghorn; Scott Rodeo; Russell F Warren; Suzanne A Maher; Lawrence J Bonassar Journal: Clin Orthop Relat Res Date: 2011-10 Impact factor: 4.176
Authors: B A Lakin; D J Ellis; J S Shelofsky; J D Freedman; M W Grinstaff; B D Snyder Journal: Osteoarthritis Cartilage Date: 2015-06-09 Impact factor: 6.576
Authors: Vincent J Baro; Edward D Bonnevie; Xiaohan Lai; Christopher Price; David L Burris; Liyun Wang Journal: Bone Date: 2012-03-17 Impact factor: 4.398
Authors: Gregory D Jay; Jahn R Torres; David K Rhee; Heikki J Helminen; Mika M Hytinnen; Chung-Ja Cha; Khaled Elsaid; Kyung-Suk Kim; Yajun Cui; Matthew L Warman Journal: Arthritis Rheum Date: 2007-11