Cartilage covers the knee's bones. With wear and tear, cartilage gradually softens, then cracks, and finally develops large holes. Without cartilage to serve as a shock absorber, knee bones rub against each other, causing pain and more damage.
The technique used in this study spurs knee cartilage to grow back, which could cut pain and improve knee function, write Kevin Stone, MD, and colleagues.
Stone's study appears in The Journal of Arthroscopic and Related Surgery.
Stone's study included 125 patients who were about 46 years old, on average. Cartilage on the weight-bearing part of their knees had worn away in large patches.
The surgery was done using arthroscopy, which is less invasive than knee replacement. In arthroscopy, doctors make a small incision in the knee and insert a pencil-sized instrument called an arthroscope.
For each patient, the researchers took cartilage from another part of the knee and crushed the cartilage into a paste. After roughing up the cartilage surface, the paste was spackled over the damaged area. The goal was for cartilage-producing cells in the paste to take root and make more cartilage.
The patients were followed for up to 12 years. More than eight out of 10 were considered a "success," write Stone and colleagues. In those patients, knee pain fell and knee function improved.
The biggest average improvements were in pain and in going up or down stairs. The results didn't vary by sex, age, or previous surgery, the study shows.
Later on, the researchers checked 66 of the patients' knees. They found signs of regrown cartilage in 42 cases. In 18 cases, regrown cartilage looked the same as normal cartilage, Stone's team reports.
The regrown cartilage was "very durable for two to 12 years in most patients," the researchers write. Stone's team notes that further studies should be done.
Meanwhile, they call the technique "cost-effective" and note "excellent, long-lasting pain relief; restored function; and the possibility of tissue regeneration" for such patients.
"While we cannot make normal cartilage, repair tissue may be sufficient for patients to 'buy time,' await newer cartilage regeneration procedures, and ultimately delay joint [replacement]," write the researchers."