Stem Cell Injections: Emerging Option for Joint Pain Relief

One option to repair a damaged knee and avoid surgery

Are you suffering from chronic joint pain? If so, you may want to ask your doctor whether stem cell injections are right for you. If you want to avoid the surgical route of repairing a damaged knee or treating an arthritic shoulder, a stem cell injection may give you the relief you need.

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What are stem cells?

Stem cells are special types of cells with the ability to self-renew or multiply. They have the potential to replicate any cell in your body. In other words, they can become a cartilage cell, a muscle cell or a nerve cell, says orthopedic surgeon Anthony Miniaci, MD.

“They have a tremendous capacity to differentiate and form different tissues, so that’s the thought behind regenerating cartilage, regenerating nerve cells and healing any injured tissues,” he says.

The source of stem cells is found in your own bone marrow or fat or you can also receive stem cells from donor sources, particularly amniotic sources such as the placenta or the amniotic fluid and lining surrounding a fetus. These cells are not part of the embryo, Dr. Miniaci says.

“The number of stem cells  that you have and their quality and activity diminish as you get older,” he says. “Amniotic stem cells, on the other hand, are  from  young tissue, so theoretically these are younger, more active cells.”

How stem cell treatment works

The treatment team harvests stem cells from your bone marrow or fat or uses donor cells . Later on, your treatment team injects the cells precisely into your joint, ligament or tendon.

Theoretically, the cells will then divide and duplicate themselves and develop into different types of cells depending on the location into which they have been injected. For example, if you have damaged knee cartilage, stem cells placed near the damaged cartilage can develop into new cartilage tissue.

However, for patients with a severe loss of cartilage or no cartilage at all, a stem cell injection is unlikely to create a new joint, Dr. Miniaci says.

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“Severe loss of cartilage typically leads to bone erosion or bone deformity, so a stem cell injection is highly unlikely to work in terms of reversing those changes,” he says.

It can, however, improve your symptoms of pain and swelling.

“The earlier you can treat someone’s joint pain, the better chance this has of working, making it less painful for the patient, less inflamed, and improve their function,” he says.


The main risk from a stem cell injection is in harvesting the stem cells. When taking the cells from your bone marrow, the treatment team inserts a large needle into your pelvis and removes some blood and the cells.

“Any time you  make incisions or insert sharp instrument into somebody’s pelvis, they can have problems such as acquiring an infection,” Dr. Miniaci says.

“If you’re taking the stem cells from fat, you you can remove some out from under the skin,” he says. “Again, you have a risk for an infection because we’re making little nicks into the skin to get to the fat.”

Treatment is in its infancy

While the use of stem cell injections to treat joint pain holds much promise, Dr. Miniaci cautions that this treatment option is still very new. Researchers need to study its effectiveness further.

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“We don’t have a lot of data or proof indicating that stem cell injections actually repair the joint,” he says.

He explains that if you have cartilage or bone damage, stem cells can differentiate and produce bone and cartilage and tissues. So, theoretically, they could heal damaged tissue within a muscle, tendon, bone or cartilage.

“That’s the theory behind it, but this type of treatment and research is just in its infancy,” he says.

“We really don’t know what’s effective, what’s not effective, how many cells are necessary, how many actual injections you need and how often,” he says. “Nobody knows how well it works yet. But we will eventually.”

Anecdotally, Dr. Miniaci finds that some patients can have significant improvement in their symptoms with stem cell injections. But he has not seen any proof yet that they are regrowing or regenerating a joint.

“Many people think that they’re going to come in with their arthritic joint and leave with a newer version of their knee joint. That doesn’t happen,” he says.

“What does occur is a biological reaction which makes the environment in their joints a little healthier, which probably makes it less inflamed, and as result, gives them less pain.”

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