Effects of Stem Cell Injections on Osteoarthritis

Author: Anna Parr

What is osteoarthritis?

Arthritis is caused by the deterioration of cartilage between joints of the body and has limited capabilities for self-regeneration. According to Lu, it has been shown that around 9.6% of men and 18% of women over the age of 60 have symptoms of osteoarthritis (Lu, 2019). Kumar states that chronic low back pain due to disc degeneration is one of the leading causes of disability and causes a huge social and economic impact on patients. Additionally, approximately 80% of adults have experienced low back pain at some point in their life, with percentages increasing with age (Kumar, 2017). When looking at the article by Freitag, currently, the chosen treatment for knee osteoarthritis is a total knee replacement which can result in significant complications. Additionally, 20% of patients having undergone a total knee replacement have reported persistent pain or loss of function 12 months after the procedure (Freitag, 2019). Lastly, Davatchi states that the available treatments for knee osteoarthritis are more symptomatic  than preventative. Some treatments may slow down the progress of cartilage degeneration, but none reverse it leading to more and more cartilage loss and eventually a joint replacement (Davatchi, 2016). This got health care professionals thinking that there has to be a better, less invasive way to treat osteoarthritis.

What are stem cell injections and how do they work? According to Kumar, stem cells have been recently viewed as a good source for the regeneration of the cartilage between vertebrae due to the changes it causes to the immune system and potential for changes in cartilage. These stems cells can come from umbilical cord blood, adipose tissue, or bone marrow (Kumar, 2017). Unlikeother techniques that have been used to combat osteoarthritis, the study by Lu showed that these cells can promote new cartilage-like cells as well as boost repair and regeneration of cartilage and collagen production. Studies have looked at using stem cells in multiple different joints of the body with the two most common being the low back and knees (Lu, 2019).

Does it work?

            One study by Freitag using stem cells in knee osteoarthritis reported no serious effects during the trials. Additionally, it was shown that there was a significant pain and functional improvement in the treatment groups with MRIs showing changes in disease progression  (Freitag, 2019). Another study by Kumar looked at the same stem cells in chronic low back pain and it showed improvement in pain and disability following 6 and 12 months after injection. The MRI in this study also revealed improved hydration of the treated discs which helps the joints be less stiff. Although stem cells show promise for repairing discs in the back that many be deteriorating, there was a low cell survival. This means the immune system rejected the cells due to thinking they were a foreign substance resulting in less benefits from the injection. It was reported that 90% of the transplanted stem cells had leaked out of the discs in the back following injection. This can be reduced to 50% with a co-administration of fibrin glue which is used to help promote would healing (Kumar, 2017). A different study by Lu looking at treatment of knee osteoarthritis showed improvements in joint function, pain, quality of life, and cartilage regeneration after 12 months. While stem cell injections show promise in preventing osteoarthritis, more studies need to be conducted to evaluate the safety and benefits of the intervention (Lu, 2019). Lastly, one study by Davatchi showed that there were some declines seen from 6 months to 12 months. The article states this could have been due to an advanced state of osteoarthritis in the patients as it was not seen in all of them. Overall, the stem cell injection did show benefits for the first 6 months then started to decline. However, the stem cell injected knees were still better than the control knees 5 years later (Davatchi, 2016).

Limitations to studies             Many of these studies had limitations to them that could have altered the results found. In the study by Lu, the sample size was relatively small as well as the patients in this study only had mild osteoarthritis. This means that these findings cannot be generalized to patients with more advanced osteoarthritis. Lastly, this study does not look at a long duration of therapeutic effects of the injection so there is a chance the effects are relatively short (Lu, 2019). The study conducted by Freitag also found limitations to the data including ethical considerations. It was found unethical to perform a surgical procedure on the control group if they were to receive a placebo injection. This could alter the study since both groups would know if they were the control or experimental group (Freitag, 2019). Similar to the article by Lu, Davatchi’s limitations were also a low number of patients. Additionally, this study used advanced stages of knee osteoarthritis which could produce worse results than if they used earlier stages of the disease (Davatchi, 2016). With these limitations in the study, future research is needed to determine the best stage of osteoarthritis to perform stem cell injections in as well how long the benefits of the injection may last.


Since stems cell injections are still relatively new and need more research, they are not always a good option for everyone. With the current research, subjects who have less advanced osteoarthritis would most likely be better candidates for this treatment option. Additionally, ensuring the stem cells are close matches to the subjects would be beneficial in preventing the rejection of the cells by the immune system. Although there is a lack of research on long term benefits, there is evidence showing benefits and improvements within a few years of the stem cell injection and could be a good fit for some.


Davatchi F, Sadeghi Abdollahi B, Mohyeddin M, Nikbin B. Mesenchymal stem cell therapy for knee osteoarthritis: 5 years follow-up of three patients. Int J Rheum Dis. 2016;19(3):219 225. doi:10.1111/1756-185X.12670

Freitag J, Bates D, Wickham J, et al. Adipose-derived mesenchymal stem cell therapy in the treatment of knee osteoarthritis: a randomized controlled trial. Regen Med. 2019;14(3):213-230. doi:10.2217/rme-2018-0161

Kumar H, Ha DH, Lee EJ, et al. Safety and tolerability of intradiscal implantation of combined autologous adipose-derived mesenchymal stem cells and hyaluronic acid in patients with chronic discogenic low back pain: 1-year follow-up of a phase I study. Stem Cell Res Ther. 2017;8(1):262. Published 2017 Nov 15. doi:10.1186/s13287-017-0710-3

Lu L, Dai C, Zhang Z, et al. Treatment of knee osteoarthritis with intra-articular injection of autologous adipose-derived mesenchymal progenitor cells: a prospective, randomized, double-blind, active-controlled, phase IIb clinical trial. Stem Cell Res Ther. 2019;10(1):143. Published 2019 May 21. doi:10.1186/s13287-019-1248-3