Why is cartilage avascular? Are all types of cartilage avascular?
There are no arteries and veins because these would compromise the biomechanical properties. All cartilage is avascular.
Most cartilage is located inside of the joint capsule, surrounded by the synovium.
The joint capsule receives ample blood supply while the contents of the joint rely on the synovial fluid.
There are no arteries and veins because these would compromise the biomechanical properties (creep and stress-relaxation) of the cartilaginous tissue.
Cartilage must be required to absorb loads, reduce friction, and allow mobility. For this reason, they are also aneural (no innervation).
This one reason that "bad" knees don't begin to bother a person until all or most of the cartilage is worn away.