Does it work?

Overall, there is a lack of high-quality evidence to support the use of stem cell injections to treat knee OA. A 2017 systematic review by Pas et al. reviewed 5 randomized controlled trials and one non-randomized controlled trial. They concluded that all of the studies had high risks of bias, but the studies did show improved patient reported outcomes with stem cell treatment compared to control groups. Additionally, some of the studies showed improved cartilage growth with the stem cell treatments based on radiological (x-ray) and histological (soft tissue) assessments.

There were also no serious adverse effects in any of the studies reviewed. However, since there was a lack of high-level evidence and a high risk of bias with the studies reviewed, the authors concluded that stem cell injections for knee OA cannot be recommended at this time.

Another systematic review from 2018 by Jevotovsky et al. further supports these findings. They concluded that the available evidence supports a positive effect from stem cell treatments for patients with knee OA, but there is a lack of high-quality evidence and long-term follow-up.

1. Pas, H. I., Winters, M., Haisma, H. J., Koenis, M. J., Tol, J. L., & Moen, M. H. (2017). Stem cell injections in knee osteoarthritis: a systematic review of the literature. Br J Sports Med, bjsports-2016.
2. Jevotovsky, D. S., Alfonso, A. R., Einhorn, T. A., & Chiu, E. S. (2018). Osteoarthritis and stem cell therapy in humans: a systematic review. Osteoarthritis and cartilage.