The era of anabolic medicine is here. We no longer inject cortisone and take out tissues. We now inject growth factors and stem cells, and replace tissues when they are torn or damaged. In this new age of biologic joint replacements and tissue regeneration, how do you sort out the treatments?
Stem cells are pericytes. They live on the walls of blood vessels. When an injury occurs, signaling factors in our bodies stimulate the release of stem cells from the vessels, and they migrate to the site of injury. Once there, the stem cells release growth factors and direct the healing response. Stem cells have a wide range of effects that include acting as anti-inflammatory agents, releasing natural antibiotics and stimulating collagen and cartilage formation. They are the conductors of our body’s healing response.
Stem cells are highly concentrated in the most vascular tissue: marrow and fat. Doctors can now harvest these tissues in the office or in surgery, concentrate them and inject them into a site of injury to stimulate healing.
Growth factors are produced not just from stem cells, but also from platelets in the blood stream. By taking small amounts of blood and spinning it in a centrifuge, the platelets can be concentrated and induced to release their growth factors. These factors can then be directly injected into a site of injury. (Curiously, there is a higher concentration of the growth factors responsible for tissue healing available from most platelet preparations than from most stem cell preparations.)
Over the past 10 years, numerous companies and doctors have developed their own stem cell and growth factor injection preparations. Famous athletes have traveled to Germany, Mexico and the Cayman Islands to obtain what they hoped were the most advanced and ideal injections.
So which are best? Here’s what we know at this point. Current data shows that most stem cell injections have very few true colony forming units: the measure of effectiveness of such cells. Worse, preparations of stem cells that were previously frozen are composed almost entirely of dead cells. Finally, the injected cells from many donor preparations—including most of the controversial fetal cell preparations—do not stay alive after injection into the joints long enough to produce a benefit.
That said, some stem cell preparations are quite effective at augmenting repair of tissues after injection and have produced remarkable results. Which ones to use, which applications, and when it’s best to combine stem cells with growth factors is still under evaluation. Our current bias is to use bone marrow concentrated cell prepared in the operating room at the time of use.
But the most positive news is that growth factors from blood-borne platelets do work. There is, in fact, very little difference in reported results between well-prepared growth factor injections. (Poorly prepared injections, on the other hand, have little value.) We have found that concentrations of your own platelets, derived from your own blood, appear to have the most healing potential in the soft tissue and joint injuries we treat. The results are comparable to any of the specialized preparations previously offered only abroad.
Huge amounts of research dollars and effort are being applied to optimize this new anabolic era of orthopaedic medicine. With more research we expect that the healing of a wide range of injuries will be accelerated by stimulating injections, and that the outcomes of surgical procedures will be similarly improved. The question is: Using cells, growth factors or both, can we make you better than you were before you were injured?
Dr. Kevin R. Stone is an orthopedic surgeon at The Stone Clinic and chairman of the Stone Research Foundation in San Francisco.