Defects in articular cartilage can induce osteoarthritis by causing molecular changes in the synovial fluid. The general inflammatory cytokine interleukin-1 (IL-1) plays a key role in accelerating tissue destruction and the repair mechanisms.

In a healthy joint, IL-1 and interleukin-1 receptor antagonist (IL-1Ra) are in balanced concentrations. In cases of osteoarthritis, there is not sufficient IL-1Ra produced to block the destructive effects of the increased IL-1. The result is inflammation, joint pain, and eventually cartilage destruction. In the IRAP II system, monocytes (a type of white blood cell) bind to the glass beads. The cells are then stimulated to produce regenerative and anti-inflammatory proteins without the addition of drugs. This process takes place over an incubation period of 24 hours.

IRAP II is used to treat mild to moderate osteoarthritis in animals.