Cartilage, the tough tissue cushioning our joints, doesn’t heal easily—especially in the knee, where it lacks direct blood flow. Most injuries still require surgery. But scientists at Northwestern University may have changed that.

They’ve developed a groundbreaking injectable biomaterial that successfully regenerated high-quality knee cartilage in sheep. The treatment combines a bioactive peptide—which promotes cartilage growth—with hyaluronic acid, a natural compound found in joints and often used in skincare.

Once injected, the biomaterial forms a rubber-like scaffold that dissolves over time, triggering the body’s own cells to grow new cartilage. In tests, the regenerated tissue surpassed the quality of untreated areas.

Lead researcher Samuel I. Stupp calls it a potential game-changer for conditions like osteoarthritis and ACL injuries. With promising results in sheep—whose knees closely resemble ours—this therapy could offer a less invasive, more effective alternative to current surgical treatments.