Updated 02 November 2016

Stem cells can reduce arthritic knee pain

An experimental procedure for arthritic knee pain involves extracting stem cells from a patient's own body fat and injecting them directly into the damaged knee joint.

For those who suffer debilitating arthritis in their knees, researchers report in a small study that just one injection of stem cells can reduce knee pain and inflammation.

Encouraging results

The idea is experimental: Extract stem cells from a patient's own body fat – cells known for their ability to differentiate and perform any number of regenerative functions – and inject them directly into the damaged knee joint.

"While the goal of this small study was to evaluate the safety of using a patient's own stem cells to treat osteoarthritis of the knee, it also showed that one group of patients experienced improvements in pain and function," noted Dr Anthony Atala, director of the Wake Forest Institute for Regenerative Medicine, in Winston-Salem, North Carolina. He was not involved in the study.

Read: Botox-like injection might ease runner's knee

"In fact, most of the patients who had previously scheduled total knee replacement surgery decided to cancel the surgery," Atala noted.

"These results are encouraging, and it will be interesting to see if these improvements are seen in larger groups of study participants," he added.

Atala is editor-in-chief of STEM CELLS Translational Medicine, the journal that recently published the results of the 18-patient study.

Severe inflammation

The French and German researchers point out that osteoarthritis is the most common musculoskeletal disease among adults, a so-called "wear-and-tear" chronic condition that often affects the knee joint.

Typified by the ongoing breakdown of the cartilage that connect joints and bones, the progressively degenerative disorder ultimately gives rise to severe inflammation, significant pain and often crippling disability.

Read: Can viscosupplements alleviate arthritic knee pain?

According to the Arthritis Foundation, osteoarthritis risk is driven by genetics; obesity; injury and joint overuse; other forms of arthritis; and metabolic disorders that can throw a person's iron or growth hormone levels out of whack.

No treatment can halt osteoarthritis' progress, and "no therapy is able to restore [damaged] cartilage tissue", noted study author Dr Christian Jorgensen, head of the clinical unit for osteoarticular diseases at Lapeyronie University Hospital, in Montpellier, France.

'Statistically significant' improvements

To explore the potential of stem cell therapy, the study authors focused on 18 French and German men and women, aged 50 to 75, all of whom had struggled with severe knee osteoarthritis for at least a year before joining the study.

Between April 2012 and December 2013, all of the patients first underwent liposuction to extract fat-derived samples of a specific type of stem cell. The researchers noted that these particular stem cells have been shown to have immune-boosting and anti-scarring properties, as well as the ability to protect against cell "stress" and death.

A third of the patients received a single "low-dose" injection of their own stem cells directly into their knee. Another third received a "medium-dose" injection, involving a little more than four times the amount of stem cells, while the remaining group received a "high-dose" injection packed with roughly five times as many stem cells as the medium-dose group.

Read: An MRI can spot the early signs of knee arthritis

After six months, the study team found that all three groups showed improvements in terms of pain, function and mobility.

However, only those in the low-dose group were determined to have "statistically significant" improvements in terms of both knee pain and function recovery.

More research needed

Apart from one case of chest pain (about three months after the injection), only a few patients experienced mild side effects.

The team concluded that the stem cell treatment results were "very encouraging". The opinion was echoed by Atala, who suggested that "the study shows yet another potential treatment using stem cells".

At the same time, Jorgensen and his colleagues stressed that more research with more patients will be needed before the approach can be considered a breakthrough.

That effort has already begun, with a second two-year trial now underway involving 150 patients at 10 different clinical centres across Europe.

Read more:

What is osteoarthritis?

Symptoms of osteoarthritis

Diagnosing osteoarthritis


Ask the Expert

Arthritis expert

Professor Asgar Ali Kalla completed his MBChB (Bachelor of Medicine and Bachelor of Surgery) degree in 1975 at the University of Cape Town and his FRCP in 2003 in London. Professor Ali Kalla is the Isaac Albow Chair of Rheumatology at the University of Cape Town and also the Head of Division of Rheumatology at Groote Schuur Hospital. He has participated in a number of clinical trials for rheumatology and is active in community outreach. Prof Ali Kalla is an expert in Arthritis for Health24.

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