PRP and Stem Cell
No Silver Bullet for Knee Arthritis
Knee arthritis is caused by the wearing out of cartilage in the knee. Cartilage is the cushion in the knee that allows us to move without pain in our daily lives. As the cartilage wears out, we start to hurt! All the catching, locking and deep toothache pain are because of arthritis. We have a variety of non-surgical options to treat knee arthritis. Unfortunately, if the arthritis is severe enough, these modalities are no longer effective, and the only option left is knee replacement surgery. Considering this, newer treatment options have been developed to avoid surgery. Platelet-rich plasma (PRP) and stem cell injections are two of these newer treatment options. I want to take a moment to explain these two novel treatment methods and maybe dispel some of the mystique surrounding these injections.
PRP is a product derived from a patient’s blood who visits a clinic and has their blood drawn. This blood is collected and spun in a centrifuge, which separates the blood into three layers. The top layer is the plasma. The middle layer is called the buffy coat, which contains white blood cells and platelets. Finally, the bottom layer is the red blood cells. The plateletcontaining layer is isolated and preserved, while the rest is discarded. Essentially, this concentrates a large amount of platelets into a small amount. This “platelet-rich plasma” is then injected into the patient’s knee.
The theoretical benefits of PRP are derived from platelet growth factors. These growth factors are touted to help with pain and potentially regenerate cartilage in the knee. Different doctors recommend various formulas and treatment regimens.
Some might recommend multiple visits for PRP injections depending on the diagnosis. Unfortunately, the studies on PRP injections do not support these claims. Study after study has failed to provide any significant benefits of PRP compared to other treatments currently on the market, such as a regular steroid injection. A recent study on PRP revealed that it lowered patients’ knee pain by two points on a scale of 1–10 over six months. After six months, the pain returns. Furthermore, all these patients had MRIs before and after PRP injections, and no evidence of cartilage regeneration from the injections was found.
Stem cell injections are more invasive and costly for patients than PRP. In stem cell injections, a physician extracts bone marrow from a patient. The most common area where this is done is around the pelvis, which is the place in your hips you put your hands on when you are mad at your husband or wife. A patient is sedated, and bone marrow is extracted using a large needle. These cells in the bone marrow are separated using a centrifuge. After isolating the stem cells, they are injected into the patient’s knee. Because cells are extracted from the bone marrow, this procedure can be a little bit more painful. This entire process takes a little longer and often requires a trip to the operating room, whereas a PRP injection can be performed in a clinic.
The studies on stem cells and PRP are hard to interpret at times. Numerous “recipes” for these injections make them difficult to compare across a wide range of studies. Furthermore, the severity of knee arthritis seems to matter. A 50-yearold patient with very mild knee arthritis might respond differently compared to a 90-year-old with end-stage arthritis that has been present for years. Studies on stem cell injections for knee arthritis have failed to show any long-term benefit compared to treatments already on the market. For this reason, the American Association of Hip and Knee Surgeons does not recommend using PRP and stem cell injections for advanced knee arthritis.
These injections typically are not covered by insurance and can cost anywhere from $1,000 to $5,000. When patients enquire about these options, I do not recommend it to them. The short duration of benefit for knee arthritis does not justify a patient’s high out-of-pocket expenses.
Dr. Jeffrey Pearson is a fellowship-trained orthopedic surgeon specializing in anterior total hip replacement and robotic knee replacement. To schedule an appointment, visit https://orthopedicspecialistsla.com/ or call 318-635-3052.