The objective of this study was to characterize the role of synovial fluid and hyaluronan in the frictional response of bovine articular cartilage. Seven cylindrical cartilage specimens were harvested from three fresh bovine humeral heads (4-6 months old). Reciprocal sliding motion (1㎜/s) was provided by a custom-made friction testing apparatus with a normal load of 22.3 N. From the measured time-dependent normal and frictional forces, the minimum and maximum frictional coefficients were calculated. Synovial fluid reduced the minimum frictional coefficient by -75 % and maximum frictional coefficient by -11%, while the reduction of the minimum and maximum frictional coefficients with hyaluronan was -42% and -24%, respectively To the best of our knowledge, this experimental study investigates the first such comparisons of frictional response of articular cartilage with and without synovial fluid and hyaluronan, and provides significant insights into their role in the articular cartilage friction and lubrication.
