Effect of the variation of loading frequency on surface failure of XXXX articular cartilage.

@entity291 @entity571 @entity42747 @entity2720 @entity734
BACKGROUND: Mechanical loading of @entity2720 can damage the articular cartilage surface and may lead to @entity571 . It is unknown if, independent of load, frequency alone can cause failure in cartilage. This study investigated the variation of articular cartilage surface damage under frequencies associated with normal, above normal and traumatic loading frequencies. METHOD: Cartilage on bone, obtained from @entity291 shoulder joints, was tested. Damage was created on the cartilage surface through an indenter being sinusoidally loaded against it at loading frequencies of 1, 10 and 100  Hz (i.e., relevant to normal, above normal and up to rapid heel-strike rise times, respectively). The frequencies were applied with a maximum load in the range 60-160  N. Surface cracks were marked with India ink, photographed and their length measured using image analysis software. RESULTS: Surface damage increased significantly (P  <  0.0001) with frequency throughout all load ranges investigated. The @entity734 of @entity42747 , c, on frequency, f, could be represented by, [Formula: see text] where A  =  0.006      0.23, B  =  0.62      0.23 and D  =  0.38      0.51  mm (mean      standard deviation). CONCLUSION: The increase in @entity42747 with loading frequency indicated that, increased loading frequency can result in cartilage becoming damaged. The results of this study have implications in the early stages of @entity571 .
