Summary
Objective: To describe the use of a cryogenic clamp of novel design for tensile strength testing
of tendinous and ligamentous tissues with inherently high tensile strength.
Methods: Inexpensive, easily machined steel clamps were manufactured to facilitate rapid insertion
into a standard wedge-screw grip apparatus installed on a testing system with a control
system attached. The deep digital flex-or tendon (DDFT) of six horses was trimmed
to a uniform dumbbell shape and secured in clamps using partial submersion in liquid
nitrogen for approximately 45 seconds and immediately tested. Approximate time between
removal from liquid nitrogen and failure of tendon was four minutes.
Results: Failure was achieved in all tendons tested in a region approximating a midpoint between
the clamps. Ultimate failure loads of up to 6745 N were achieved without slippage
of the tissue from the grips. The ultimate tensile strength of the normal equine DDFT
determined in this study was 111.82 ± 11.53 N/mm2, and the stress versus grip-to-grip elongation plots for our equine DDFT were representative
of a standard non-linear elastic curve obtained in similar studies.
Clinical significance: We present a low cost device for quantifying physical properties of specimens with
high connective tissue concentrations and inherent high tensile strength. Results
of this study indicate that this device provides a practical alternative to other
more costly methods of adequately securing larger tendons and ligaments for tensile
strength testing.
Keywords
Cryogenic clamp - tensile strength - deep digital flexor tendon
