For nearly three decades, Kevin Stone, MD, has been refining the BioKnee program he launched at The Stone Clinic in San Francisco to help patients with arthritis delay or avoid total knee replacement.
By replacing, regenerating or rebuilding damaged portions of knee cartilage and damaged ligaments, Dr. Stone's BioKnee program keeps patients active. He shared his predictions for the future of these biologic techniques and the reasons why they work.
Note: Responses have been edited for length and clarity.
Question: Why did you develop the BioKnee program?
Dr. Kevin Stone: We first recognized in 1991 that for each of the three tissues inside the knee, if you repair them or replace them as soon as possible after injury, then you decrease the rate of arthritis. Or, if [a patient was] already developing arthritis, if you repair, replace or regenerate the tissues, you could delay the progress and help people return to sports.
Q: What makes the BioKnee procedures (articular cartilage paste graft and meniscus allograft transplantation) advantageous?
KS: If people with injuries can have treatments that restore their tissue as opposed to taking it away, they have a good chance of returning to sports and remaining active. Unfortunately, in America today, there are over 800,000 knee meniscectomies each year. The tragedy is that even though we know that meniscectomy leads to arthritis, we have not had a big enough effect on our peers or insurance companies to change the behavior and insist on tissue restoration rather than tissue removal.
One of the great advantages of BioKnees is you don't burn any bridges. You can always do it over again if the patient … has another injury, as opposed to an artificial joint, where only the first replacement has a high rate of success and the subsequent revisions have a high complication rate. Of people with total knee replacement, 50 percent develop pain at 10 years, and there are very few solutions for them. In BioKnee replacement, we don't limit the patient's return to sports in any way. The knees feel so much more normal when you do biologic as opposed to bionic [procedures].
Q: Why is there industry resistance to restoring rather than removing tissue?
KS: There are several factors at work. Meniscus repair and meniscus replacement are technically difficult surgical procedures for many surgeons, they take longer and the insurance reimbursement isn't commensurate. The reason is that most people only stay with their insurance company for two to three years. Arthritis often takes five to 20 years to develop. The insurance company doesn't really care about the future of the patient; they care about the time in which they're insuring the patient. There's not good coverage, and there aren't good incentives for surgeons to take extra time and develop extra skills.
Q: How do you determine who's a good candidate for the BioKnee?
KS: Number one, a motivated patient who understands many of these procedures may only be temporary, [lasting about] 10 to 15 years. They may not be permanent solutions. Number two, we have to see them before [the joints] become bone-on-bone. Once the joint space is lost, it's very difficult to get a good result in a biologic reconstruction procedure.
Q: Are other practices adopting similar biologic approaches?
KS: We [at The Stone Clinic] have more experience than anyone in the world because we started so early. However, over the past five years, the biologic revolution has begun expanding rapidly in the orthopedic community. At the American Academy of Orthopaedic Surgeons [annual meeting], almost every orthopedic company had biologics solutions offerings, whereas five years ago, very few of them did.
There's huge patient demand based on the success of injections. What we have now entered is what I have named the Anabolic Era of Orthopedics. In the past, surgeons would remove tissues and inject cortisone … which weakens tissues and damages cartilage. Now, they're more inclined to put tissues back in and save them. Based on the response from patients to these anabolic therapies, physicians are now realizing they have a potent tool which helps patients and has almost no downside except the cost.
Q: What misconceptions would you like to clear up?
KS: The biggest misconception we hear from patients is, 'Doc, will stem cells re-grow cartilage in my knee?' We use stem cells not to re-grow cartilage, but to add re-growth factors to change it from a degenerative environment to an anabolic environment where there are growth factors to stimulate healing. Lubrication, stem cells and growth factors will make their knee feel better — it may protect it — but we do not have evidence it will re-grow tissues. However, if we're doing a repair surgical procedure, we do believe adding these growth factors probably augments the repair process.
We've often heard the data that 80 percent of people who are told they need a total knee replacement don't need one. That's because most commonly, there's one part of their knee that's worn out more than any other part, and that is the pain generator. If they are bone-on-bone in that compartment, a partial knee replacement solves most of those problems. If there's joint space remaining, a combination of lubricant growth factors and tissue replacement solves a great many of the problems, even in arthritic knees.
Q: What do you predict for the future of biologic therapies?
KS: As these techniques become more and more widespread, a trend will be a reduction in total knee replacement and an increase in partial knee replacements and biologic knee replacements.
I'm passionate about being able to bring these biologic therapies to the developing world because surgeons in countries that don't have a lot of resources can always use biologic therapies that are readily available and low-cost, whereas they may not have access to expensive implants. The ability to have a safe tissue bank, optimize stem cells, and repair articular cartilage with paste graft technology brings joint reconstruction to a large portion of the world that's otherwise left behind in the development of new technologies.