
The white articular cartilage has a very special internal structure, with the cartilage cells suspended in pockets within a background matrix.

Early softening of the joint cartilage of the femur - see the dimpling by the probe - is called chondromalacia.

Fibrillar wear of the articular cartilage. The yellowish bone is showing through on the top of the tibia.
Articular cartilage damage and arthritis
Articular cartilage is also called joint cartilage or hyaline cartilage. It is damage to the articular cartilage which is called 'arthritis' and in the knee all efforts are geared towards preventing any damage or breakdown of this all-essential joint surface, as it has a poor blood supply and does not heal well if damaged.
CLINICAL PUBLICATIONS
The Basic Science of Articular Cartilage - Structure, Composition, and Function. Fox AJS, Bedi A and Rodeo SA. Sports Health. 2009 Nov; 1(6): 461–468.
Articular cartilage: structure and regeneration. Becerra J, Andrades JA, Guerado E, Zamora-Navas P, López-Puertas JM, Reddi AH. Tissue Eng Part B Rev. 2010 Dec;16(6):617-27.
Imaging of articular cartilage. Paunipagar BK and Rasalkar DD. Indian J Radiol Imaging. 2014 Jul-Sep; 24(3): 237–248.