Advancing the Science

Mayo Clinic Medical Science Blog – an eclectic collection of research- and research education-related stories: feature stories, mini news bites, learning opportunities, profiles and more from Mayo Clinic.

June 8, 2017

Knee Deep

By angelabingham


Treating knee disorders with regenerative medicine

Mayo Clinic's Center for Regenerative Medicine is supporting four studies to help people delay or even prevent costly knee replacements.

The costs of musculoskeletal disorders are staggering. They are the most common health conditions in the United States among all age groups, with half of all Americans reporting at least one chronic musculoskeletal condition.

According to a joint project of leading orthopedic societies in the United States, musculoskeletal disorders for work-related injuries account for one-half of all days away from work. A decade ago, these conditions cost Americans nearly $1 trillion in health care costs and lost wages. That's an astounding 7.4 percent of the gross domestic product in the U.S. The problem has only gotten worse since then.

The latest figures from the Centers for Disease Control and Prevention show that from 2000 to 2010 the number of knee replacements nearly doubled.

And the United States is just at the beginning of the surge of retiring baby boomers, who are more active than earlier generations of retirees, so it is anticipated that the demand for knee replacement services will climb sharply.

In addition to societal impact, knee conditions can be devastating on an individual level. They cause substantial pain and can dramatically decrease quality of life for anyone at any age — active adolescent athletes who rupture a ligament or damage cartilage; healthy middle-aged adults who incur wear-and-tear disorders; and vibrant retirees who lose independent living and acquire chronic diseases such as diabetes and hypertension because of arthritis. These conditions are incredibly complex, involving bones, muscles, ligaments, tendons and cartilage.

To help people delay or even prevent costly replacements, Mayo Clinic's Center for Regenerative Medicine is supporting four studies aimed at different parts of the knee.


Mayo Clinic has launched the first study in the U.S. to treat knee arthritis with stem cells harvested from fat tissue and grown in a lab. Compared to trials with bone marrow concentrate, this trial will inject millions of purified stem cells into arthritic knees to study the ability of these cells to reduce symptoms and regenerate damaged tissue.

Researchers will follow subjects with a variety of measures, including cartilage-sensitive MRI scans. With this information, Mayo researchers will build a foundation for further stem cell research and develop ways to tweak the stem cells in future patients to enhance their healing ability.


Your body is filled with healing cells, growth factors and proteins. To treat knee arthritis, Mayo Clinic researchers are testing platelet-rich plasma, which is rich in all three.

The technique starts with a patient's own blood, and researchers centrifuge it to concentrate the platelets into a small volume of plasma. Platelets contain several growth factors that aid in healing. The enriched plasma is then injected back into the patient to reduce pain and inflammation, improve function and promote healing.


Similar to platelet-rich plasma, your body contains bone marrow rich in proteins and growth factors. However, bone marrow also contains stem cells, which are powerful cells capable of reducing inflammation, promoting cell division and potentially slowing down arthritis.

When concentrated, bone marrow delivers a robust mix of proteins, stem cells, platelets and other cells. The quantity of stem cells available for most bone marrow concentrate procedures is small — approximately 50,000 per injection — but bone marrow concentrate has demonstrated success for improving knee conditions such as arthritis. Mayo Clinic researchers are studying the components of bone marrow concentrate to determine optimal dosing and treatment regimens.


Researchers know that injections of a specific protein — interleukin-1 receptor antagonist protein (IRAP) — will help reduce swelling in the knee joint. Unfortunately, the effect doesn't last long, as the protein is gone within 30 to 60 minutes.

However, researchers at Mayo Clinic are developing a gene that produces the protein and are placing it into a virus that can be injected into the knee. With the help of the virus, the gene "infects" the native knee cells so that the body produces the protein for up to a year. Researchers expect to launch a phase I trial within a year.


Mayo Clinic is a nonprofit organization committed to clinical practice, education and research, providing expert, whole-person care to everyone who needs healing. This article was originally featured on the philanthropic site "You Are...the campaign for Mayo Clinic."

More information:

Visit Mayo Clinic's clinical trials website for information on some of the currently available knee-related trials and many others.

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