CHANGCHUN -?Chinese surgeons have successfully transplanted regenerated cartilage on a patient's damaged knee joint using German technology.

The patient, a 42-year-old man, received the one-hour surgery last Thursday at the People's Hospital of Jilin Province in northeast China. He is in stable condition and will leave hospital soon.

Zhang Liheng, director of the hospital's sports medicine center, said Monday that the operation was conducted in cooperation with a Germany research institute and biotechnology company.

Doctors extracted cartilage tissue cells from the patient and grew them outside the human body for about 12 days, completing the surgery after the cells had grown into new cartilage tissue.

Hyaline cartilage is the tough, flexible tissue that serves as a cushion for bones around the joints, preventing them from rubbing against each other during physical activities. When the tissue is damaged, normal movement of the joints becomes limited, and patients can suffer from severe pain or even disability.

In the past, clinicians had to substitute the tissue with other materials, and movement of the joint would not fully recover. With the latest regeneration technology, the cartilage can be repaired and damage to the joint cured permanently.

"China also has its own cartilage regeneration technology, which is mainly in the clinical experiment stage," Zhang said.