The concept of the chondron as a biomechanical unit

Five decades have passed since the publication of a series of classical papers by BENNINGHOFF (1922, 1924, 1925a, 1925b) in which he introduced the concept of the chondron as a fundamental unit of cartilage tissue. Although considerable progress has been made during the recent years in the understanding of the structure and the chemical composition of cartilage and, furthermore, the field of biomechanics and bioengeneering has opened many new perspectives, the problem of the mechanical properties of cartilage in relation to its structural organization is still far from being completely elucidated. It is remarkable how little attention has been paid in this respect to the possible significance of the chondron, which — in the conception of BENNINGHOFF — should be an important element in the reaction of cartilage to mechanical stress. The purpose of this brief paper is to attempt to answer three questions in this connection: What exactly meant BENNINGHOFF by his concept of chondron ? What is the explanation of the fact that this concept apparently fell into discredit ? What is the significance of the chondron when it is reexamined with present-day tools ?