Home › Blog › Ask Dr. C- Episode 8- Bone on Bone and Cartilage Regeneration

Nothing in regenerative medicine is likely more misunderstood by doctors and patients than “bone on bone” knee arthritis. There are misconceptions about candidacy as well as what the patient can expect as far as outcomes. Hence, this is a great “Ask Dr. C” question.

Dr. Centeno, ” you said that you have not been able to grow cartilage in arthritic knees”. I was wondering if that is a goal of your research, and if you are working on any type of matrix to hold the seem cells in place? Do you have any idea of how long it will be before cartilage can be grown in arthritic knees, or bone on bone knees?

We can break this question and the many like it into a couple of parts:

• What is arthritis and why does it hurt?
• Candidacy for Real Stem Cell Procedures
• What Bone on Bone Patients Can Expect
• The Future?

Let’s dig in…

What Is Arthritis and Why Does It Hurt?

Your knee joints have cartilage on the end of the bones that act as a cushion. In the process of knee arthritis, cartilage is lost, and eventually, the bones change shape and develop “bone spurs”. Other changes occur in the bone as it breaks down. More on those below.

One of the biggest misconceptions for patients and physicians alike is that cartilage loss causes pain. Regrettably, the government research on imaging findings and pain doesn’t bear that one out. Meaning many people have cartilage loss who are walking around without knee pain. So what causes pain?

The most consistent MRI finding associated with pain is swelling in the bone called Bone Marrow Edema (BME) or a Bone Marrow Lesion (BML). Hence the serious research on knee pain due to arthritis has shifted from cartilage loss to this bone marrow swelling. However, that shift in research focus has been recent, hence many physicians still have a “cartilage fetish”.

So while cartilage is important for maximal functioning at young activity levels, it’s loss is not what causes pain. In addition, in a bone on bone knee, there is no way to regenerate large stretches of cartilage with any surgery, hence the only option is to replace the joint. So the real question for regenerative medicine becomes, in patients with bone on bone knee arthritis, can we get similar pain and functional results without replacing the knee and by using a real stem cell procedure? Meaning the knee that has been amputated and had a prosthesis inserted will never perform like a young knee, so can you get the same results without amputating the joint?

Candidacy for Real Stem Cell Procedures

There’s a bizarre misconception among many physicians that the severity of the knee arthritis links directly to whether the patient will respond to a stem cell procedure. In other words, more severe knee arthritis patients (bone on bone) must be poor candidates for an injection procedure. This misconception comes from how these patients respond to other types of surgical or injection procedures, but based on our published data, it really doesn’t apply to a real stem cell procedure.

First, what is a real stem cell procedure? I use that term because right now patients are getting bombarded with scam clinic offerings of umbilical cord “stem cells”. These products have no living and functional stem cells (see my video below), so when I discuss a real stem cell procedure, these are the qualifications:

• The patient’s own high dose bone marrow concentrate is being used
• This is being placed into the knee joint and bone using imaging guidance
• Other tendon or ligaments issues are also being injected using imaging guidance

Second, when we have looked at our data, we don’t see a clear association between “bone on bone” arthritis and outcome. Meaning patients who had less severe arthritis did no better than patients who had bone on bone. This is now confirmed by other data published by other authors.

What Bone on Bone Patients Can Expect

One of the crazier scams out there right now is showing patient “before and after” knee x-rays in ads. These are mostly placed by chiropractic and alternative medicine clinics offering fake stem cell therapies. This gives the incorrect impression that the goal of a stem cell procedure is to regrow the patient a new knee. If that’s not the goal, then how do these procedures work?

First, we have the “stem cell” knee x-ray scam. To see how that works, check out my video below:

Second, if real knee stem cell procedures won’t regrow a bone on bone knee arthritis patient’s knee, how do they likely work?

• Replacing a Worn Out Stem Cell Reserve: Our knees have native stem cells. The number of those cells available for repair and maintenance goes down as we age and get arthritis. Hence, one of the goals of a stem cell procedure is to replace those cells.
• Rebooting Dying Stem Cells: Studies have shown that mesenchymal stem cells have the ability to give their good batteries (mitochondria) to cells that have worn out batteries, rebooting those dying cells.
• Healing the Bone Lesions-As we discussed, it’s the bone that hurts, which is why we often treat the microfractures in the bone with bone marrow stem cells.
• Rebooting the Nasty Witches Brew: The environment inside an arthritic joint is a nasty witches brew of inflammatory and pro-breakdown chemicals. One goal is to reboot that and make those chemicals tilt toward the side of regeneration.

There may be other mechanisms as well.

The Future?

Do I think it will be possible to regrow large amounts of cartilage for bone on bone knee arthritis patients in the future? Not in the next ten years. Why? The technical issues in repairing that kind of large scale cartilage loss are too daunting. It will take more than the right chemical or the right stem cells or the right matrix. That doesn’t mean that we can’t do small scale cartilage repair now with stem cells or other things that will hit the market in the next decade. However, that’s like fixing a pothole versus building a whole highway. For more on MRI results on fixing small cartilage potholes, see my video below:

In the long-term future, it may be possible to 3D print new meniscus tissue and regenerate large stretches of cartilage, but I suspect the focus will be on prevention and early treatment. Meaning when we have reliable ways to easily fix cartilage that are widely covered by insurance, the focus will shift to early detection and regeneration to avoid the knee from getting to a “bone on bone” category.

The upshot? This is a super common question that I get, so I am happy to have had the opportunity to answer it! Keep the great questions coming!

Chris Centeno, MD is a specialist in regenerative medicine and the new field of Interventional Orthopedics. Centeno pioneered orthopedic stem cell procedures in 2005 and is responsible for a large amount of the published research on stem cell use for orthopedic applications. View Profile