Articular cartilage

Question 1

Function of articular cartilage

Answer 1

Joint lubrication
Shock absorption

Question 2

Biomechanical properties of cartilage

Answer 2

Biphasic material that is viscoelastic

Cartilage undergoes creep and stress relaxation

Freely permeable to water

Anisotropic: different mechanical propertie depending on direction in which it is loaded

Question 3

Type of lubrication in articular cartilage

Answer 3

Boundary lubrication: Prevent direct articular contact, most important at rest or under load

Fluid-film lubrication

Elastohydrodynamic lubrication
I. Predominant lubrication mechanism in synovial joints during dynamic joint function
Occurs as speed increase and similar to squeeze film

Question 4

Injury and healing of articular cartilage

Answer 4

Superficial lacerations do not heal ; completely avascular

Deep lacerations that extend below tidemark, to subchondral bone resulting in haematoma, fibrin clot and activation of inflammatory response