The inside surface of the knee joint is lined with a tough articular cartilage that has a slippery texture which allows smooth movement. This cartilage does not have a blood or nerve supply. This means any damage to the articular cartilage cannot be naturally repaired. With age-related wear and tear, the joint gradually degenerates and becomes increasingly painful. Athletes can sometimes injure the articular cartilage from trauma.
The number of knee replacement surgeries performed in the United States has been steadily increasing. In 2010, nearly 700,000 Americans above the age of 45 underwent total knee replacement or joint arthroplasty procedures. More than 5 million knees have been replaced in the last decade or so. An estimated 200,000 people undergo knee and hip replacement in the United Kingdom each year.
Women have a 50 percent higher rate of total knee replacement surgeries than men. Not unexpectedly, the procedure is more commonly performed in those over the age of 65. The surgery is offered to patients who have osteoarthritis of the knee and do not experience pain relief with medications or walking supports. The surgery allows patients to resume a normal lifestyle but it is associated with a number of risks and complications. In addition, patients must undergo extensive rehab, recovery, and exercise therapy.
Scientists are trying to discover ways to repair the damaged knee cartilage when an individual is still young. The hope is that this will prevent the development of arthritis and avoid joint replacement surgery in later years. The idea is to use stem cells to regenerate the damaged cartilage. Stem cells can grow into all types of cells found in the human body.
Researchers have been employing a complex and expensive stem cell treatment which attempts to realign arthritic knees in a two-step process. In the first stage of the procedure, stem cells are harvested. In the second stage a few weeks later, the tissue is reintroduced to heal the injured joint.
Now, a team of doctors at the Royal National Orthopedic Hospital in Stanmore has developed a less complex one-stage procedure. In this surgery, stem cell harvesting takes place from the bone marrow of the pelvic bone. Precursor cells are then prepared onto a matrix which is introduced into the damaged knee during the same procedure. The stem cells serve as seeds for new cartilage.
Early results are encouraging. Approximately three-fourths of treated patients experienced a reduction in pain and improved outcome with results comparable to the more complex two-step process. It is expected that the one-stage procedure will be less expensive than the two-stage surgery.