Strain field measurements applied to articular cartilage using digital image correlation

Kinga Czerbak, Sally Clift, Sabina Gheduzzi

Research output: Contribution to conferenceAbstractpeer-review


Osteoarthritis is one of the most common musculoskeletal diseases. It involves degeneration and loss of articular cartilage, leading to a painful bone on bone
articulation during movement. Numerical FEA models exist to predict the mechanical behaviour of degenerated cartilage. One of the limitations of these models
arises from the poor validation that can be attained with traditional experimental data. This typically relies on comparison with global mechanical quantities such as
total tissue strain, which mask the individual contributions originating from the different layers. In order to improve on this, an experimental method was developed
to visualise the through-thickness behaviour of articular cartilage.
Four experiments were performed on hemi-cylindrical cartilage plugs, harvested from a porcine femoral head, and immersed in a fluid solution. An Indian
ink speckle pattern was applied to the flat surface of each hemi-cylinder. The specimens were equilibrated in 2.5M NaCl solution, transferred to a custom designed
testing rig, and a reference image of the tissue cross-section was taken.
The solution concentration was then decreased to 0.15M and, predictably, the tissue thickness changed. Images of the tissue cross section were taken
every 60s for the duration of the experiment (3600s). All images were analysed using a DIC algorithm (Ncorr open-source 2D digital image correlation matlab
program), and documented the strain changes through the tissue thickness as a function of time. The measured total strain in the tissue was consistent with that
reported by Lai et al. (1991). However the present technique allows to quantify the strain contribution from any of the tissue layers or sublayer. This poses a
significant advantage over traditional methods as resulting information can further the understanding of the factors contributing to the mechanical behaviour of the
tissue and provides an ideal platform for validating more and more refined models of tissue behaviour
Original languageEnglish
Publication statusPublished - 5 Sept 2016
EventBritish Orthopaedic Research Society Annual Meeting - Glasgow University Union, Glasgow, UK United Kingdom
Duration: 5 Sept 20166 Sept 2016


ConferenceBritish Orthopaedic Research Society Annual Meeting
Country/TerritoryUK United Kingdom


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