Torn meniscal cartilage, which affects about 80,000 men and women in Britain every year, is so difficult to repair that many professional sportsmen opt to have it removed altogether, risking osteoarthritis in later life.
The cartilage acts as a shock absorbing cushion between the bones of the upper and lower leg and is frequently torn by twisting the leg during activities such as jogging, football, horse riding or skiing.
Martin Petrov, a winger for Manchester City, is currently out of the game for four months as a result of the injury.
Scientists at Bristol University have now managed to heal cartilage tissue in a laboratory with stem cells taken from a patient's own bone marrow. They placed the cells inside the tear, held in place by a spongy scaffold made from collagen, and found the stem cells brought the two pieces of torn cartilage together.
Anthony Hollander, professor of rheumatology and tissue engineering and leader of the team that made the breakthrough, will now test out the treatment on their first patients.
He said: "The stem cells knit across the two sides of the lesion and cause a reuniting of the two sides. We hope that in the patient we can reunite the cartilage in a strong enough way to heal the wound completely."
Jonathan Webb, a rugby full-back who played 33 times for England, became a victim of a meniscal cartilage injury in 1989.
Webb, 45, who became an orthopaedic surgeon specialising in sports injuries after retiring from professional rugby, had cartilage removed but still needs repeated surgery on his knee.
He said the stem cell breakthrough offered "the opportunity to rebuild the meniscal cartilage if it cannot be repaired. It may be that the professional sportsmen, who have the most to lose, will drive the technology forward".