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Effect of in vitro testing over extended periods on the low‐load mechanical behaviour of dense connective tissues
Author(s) -
King Graham J. W.,
Pillon Corrie L.,
Johnson James A.
Publication year - 2000
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.1100180422
Subject(s) - in vitro , connective tissue , materials science , composite material , chemistry , medicine , pathology , biochemistry
Many biomechanical studies are performed on dense connective tissues in the laboratory over a substantial time period; however, the effect of the in vitro testing environment on the cyclic load‐relaxation behaviour of these structures is not well established. This study evaluated the effect of long duration of testing on ligament viscoelastic behaviour, using the rabbit femur‐medial collateral ligament‐tibia complex as a model. Dissected rabbit knee joints were mounted on a materials testing machine, and isolated ligament complexes were cycled at a frequency of one cycle/min to a fixed displacement of 0.7 mm for an 18‐hour period. After an initial period of exponential load relaxation, the cyclic peak loads slowly decreased over the 18‐hour period. The average decrease in the cyclic peak load between 0.5 and 18.0 hours was 0.26% (of the original peak load) per hour (r 2 = 0.934), or a total of 8.6 ± 4.6% over this period (p < 0.0001). Thus, lowload testing of dense connective tissues in the laboratory over extended periods significantly alters their biomechanical behaviour, and these changes should be considered in long‐term laboratory‐based studies of dense connective tissues.