Bulletin No. 2, 2024

Her camaraderie with Professor Yung furthers the synergy of their eOCT research Rekindling patients’ hope for cartilage repair According to The Lancet , about 595 million people worldwide were living with osteoarthritis in 2020, up 132.2% since 1990. The knee joint is the most common site for degenerative joint diseases such as osteoarthritis, a condition that causes pain, swelling and stiffness. Without blood vessels, cartilage cannot heal on its own once injured. In the worst- case scenario, the patient’s knee joint needs to be replaced by an artificial one. Professor Yung, who is responsible for the handling of joint replacement cases in the Hospital Authority’s New Territories East cluster, says his team handles 1,000 cases per year but there are 4,000 to 5,000 cases on the waiting list. “And the list is getting longer as our society is ageing rapidly,” he says. “Knee joint replacement is the most common orthopaedic surgery in Hong Kong. It takes around four to six years for patients to receive knee joint replacement surgery.” Surgical procedures, such as microfracture and autografting, can be used to treat traumatic cartilage damage but there are significant drawbacks. Microfracture involves drilling tiny holes into the bones underlying the damaged cartilage, but cartilage repaired in this manner is of poor quality and will degenerate quickly. Autografting involves harvesting a graft from a part of the joint to replace the damaged cartilage and is the clinical gold standard. However, owing to the severe side effects, such as chronic pain and degeneration due to injury of the autograft donor site, this procedure is no longer offered by surgeons. Professor Yung has been applying matrix-induced autologous chondrocyte implantation (MACI) for two decades, a procedure in which a patient’s own cells are used to regrow new cartilage for the knee joint. The patient’s harvested cells are placed onto a film trimmed by the surgeon for implantation into the damaged area to regrow new cartilage. “It usually takes more than 18 months to fill part of the defect area, but Professor Chan’s eOCT plug can completely fill the area immediately.” These regenerative complex tissue plugs allow orthopaedic surgeons to use the minimally invasive arthroscopy procedure to repair cartilage damage without the need to hurt the patient’s own cartilage, like the existing surgical procedures do. “We grow the cartilage tissues in vitro using the patients’ own stem cells and use the engineered cartilage to replace the damaged tissues. We are now translating this technology for use on humans,” adds Professor Chan. The performance of eOCT has been proven comparable with autograft transplantation in animal studies. Chinese University Bulletin 12 | Professor Barbara Chan