CARTILAGE DEFECT AND OSTEOARTHRITIS

ARTICULAR CARTILAGE IS :
A soft white tissue that covers the ends of the bones and helps joints to move smoothly.

A non-vascular tissue with limited capacity for self repair.

Consisting of cells named chondrocytes embedded in an extracellular hyaline matrix.

Composed of a hyaline matrix with specific biomechanical properties to absorb shocks particularly in the main load-bearing joints, such as the knees.

CARTILAGE defect:
Aging and repetitive trauma occurring during intensive sport practice are the major risk factors for cartilage degeneration.

Cartilage upon injury can often evolve towards osteoarthritis (OA).

High prevalence  of  OA patients are aged over 60, representing 15-20%  of the population.

The state-of-the-art long-term solution for advanced OA is joint replacement by prosthesis for the knee
Not commonly proposed to patients under  the age 60.
Lifetime of the prosthesis is limited to 15-20 years.
Pain relief is not completely attenuated for the majority of patients.

MANY PALLIATIVE TREATMENTS BUT NO SOLUTION TO REGENERATE THE CARTILAGE :
Treatment goals : reduce symptoms, improve function and Prevent degeneration

Medications such as anti-inflammatory drugs alleviate pains but with severe side effects.

Injection of hyaluronic acid or platelet rich plasma are only palliative treatments.

Microfracture of subchondral is a gold standard treatment for small cartilage lesions (<2 cm2) but produce the formation of fibrocartilage of poor quality and therefore non long-lasting treatment.

IN VITRO CARTILAGE TISSUE ENGINEERING IS CHALLENGING :
Difficulty to multiply cartilage cells (chondrocytes) in culture increases with patient age and is very difficult after the age 55.

Chondrocytes lose rapidly in culture their original function which is the capacity to synthesize hyaline cartilage matrix and dedifferentiate into fibroblastic-like cells.