Osteoarthritis of the Human Knee

Osteoarthritis is a disease that has been characterised historically by the focal destruction of cartilaginous tissue and hence, is defined as such. However, recent investigations have brought this pathology into contention with significant evidence implicating subchondral bone in the disease's pathophysiology. Early-stage primary osteoarthritic bone samples were harvested from both presenting medial and and non-presenting lateral compartments of diseased human tibia and were used to investigate the role of subchondral bone in the pathogenesis of primary human osteoarthritis. Significant differences in intrinsic tissue stiffness and mineralisation were observed in all samples presenting with clinically-defined, early-stage OA. Interstingly, non-presenting lateral samples also exhibited significant differences in stiffness and mineralisation. Hence, the presence of an early, non-presenting stage of OA initiation was observed in the bone tissue of these samples prior to overlying cartilaginous tissue damage. In conclusion, the classic 'wear' and 'tear' definition of this disease is no longer applicable to human knee OA.