Articular cartilage is the smooth slippery layer covering the portion of bones inside the joint. Localised defects of this cartilage can be repaired by arthroscopic techniques like microfracture, mosaic-plasty, osteochondral transfer (OATS), or by two-stage procedure using cartilage cell culture techniques (ACI).  In OATS or mosaic-plasty, healthy cartilage plugs from unimportant areas in the knee are used as “spare parts” to replace lost cartilage in important weight bearing areas.

In ACI, a small sample of healthy cartilage is harvested through arthroscopic surgery, and sent to the lab where it is processed and incubated to get a huge number of healthy cartilage cells in 6 to 8 weeks’ time. The knee is then opened and these cells are implanted using a gel matrix to cover the cartilage defect at the second stage operation.