Novel measurement of surface roughness of articular cartilage using biospeckle

What is it about?

the article is about measuring the nanoscale surface roughness of articular cartilage using a novel non-contact and non-destructive optical method based on biospeckle imaging. to do that, an experimental setup was implemented to capture biospeckle images from twelve cross-section areas of articular cartilage tissue gathered from bovine knee joints at 632 nm wavelength laser radiation. Then, to analyze the biospeckle image, a second-order statistical-based method was proposed through the combination of 308 highly correlated statistical features extracted from implemented gray-level co-occurrence matrices (GLCMs) by employing principal component analysis (PCA). Articular cartilage is a thin layer of glassy-like connective tissue that covers the ends of joint bones with no nerves or blood vessels. Its thickness varies according to the species, location, age, gender, and weight where it ranges from 1 mm to 6 mm in the human knee joint. The articular cartilage reduces the friction between the interacting bones to permit the movements of one bone against another, supplies shock-absorbent of the body, and protects the bones from excessive loads where they can bear 2.5–5 times body weight during the walk.

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Photo by Ernest Karchmit on Unsplash

Photo by Ernest Karchmit on Unsplash

Why is it important?

Osteoarthritis is a public health issue that describes articular cartilage degeneration. It can be caused by the erosion of the articular cartilage tissue resulting in cracking and thinning of this connective tissue surface that in advanced stages can be gradually worn out to the bone surface, i.e. naked of articular cartilage. Articular cartilage of knee joints can be damaged by genetics, overweight especially in women, leg curvatures, age, knee injuries, and repeated stress on the knee like climbing stairs, cycling, and long time sitting. Thus, the nanoscale average surface roughness of articular cartilage is an essential symptom of osteoarthritis because the earliest sign of osteoarthritis is fibrillation of the articular cartilage surface; it has to be measured quantitatively. Yet, clinical diagnostic tools, such as magnetic resonance imaging, computer tomography, arthroscopy, and plain x-ray provide a qualitative investigation of osteoarthritis and cannot detect osteoarthritis in the early stage.

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