- PRP concentrates your own platelets, which release growth factors. Stem cells signal to the tissue around them. Both are injected into the joint.
- In the meta-analyses, adipose stem cells ranked best for pain at six months and leukocyte-poor PRP for function and tolerability.
- PRP fits a mild, recent injury. It does not rebuild tissue that is no longer there, such as a worn meniscus or advanced cartilage loss.
Most pages on this subject are written as a ranking, with one option winning. That framing is wrong, and it is why so many patients end up paying for the treatment that did not fit their problem.
The two do different jobs. PRP is a concentrate of your own platelets, which release growth factors into the tissue. Stem cell therapy delivers cells that signal to the environment around them. Both are injected into the joint. That is where the similarity ends.
Which one fits depends on what is damaged in your joint, and for how long it has been that way.
What the comparisons actually show
A network meta-analysis pooled 43 randomised trials comparing hyaluronic acid, two types of PRP, bone marrow stem cells, adipose stem cells and saline placebo (Zhao et al., 2021). The results are more interesting than a winner.
At six months, adipose stem cells ranked best for pain, while leukocyte-poor PRP ranked best for function. At twelve months both still beat placebo for pain, and PRP held its advantage for function. On safety, every option except leukocyte-poor PRP produced more treatment-related adverse events than placebo.
A larger analysis of 79 trials and 8,761 patients ranked cell-based preparations highest for pain and function at up to one year of follow-up (Anil et al., 2021).
Read those together and the pattern is clear. One option ranked better for pain, the other for function and tolerability. That is the signature of two different tools, not of a winner and a loser.
There is a further wrinkle most centres skip: “PRP” is not one product. A 2025 analysis of 23 trials found that the best preparation depends on the stage of the disease — different platelet and white-cell concentrations suited early versus advanced osteoarthritis (Yu et al., 2025). If nobody tells you which PRP you are getting, that is worth asking about.
How we decide in practice
The first question is never which treatment you would like. It is what the imaging shows, what is damaged, and how long it has been damaged.
PRP has a real place: a mild, recent injury, where the tissue is still largely intact and needs a signal to finish healing. In that situation it is a reasonable option and, by the safety data above, a well-tolerated one.
Where PRP is not the route is established structural damage — a worn meniscus, advanced cartilage loss. Growth factors do not rebuild tissue that is no longer there. We tell patients this even when PRP is the cheaper option, because sending someone home with the wrong treatment costs them more than the price difference.
In our own practice we apply mesenchymal stem cells. Never corticosteroid alone, and never PRP alone. Depending on the case the cells may be combined with exosomes or with PRP, but the cells are always the treatment.
Dosing follows the joint. A large joint — knee, hip, shoulder — receives 50 million cells with exosomes; a small joint such as ankle, wrist or elbow receives 30 million. Peripheral joints are injected under ultrasound guidance with local anaesthesia, so the cells reach the space the assessment identified.
Recovery, and the honest limits
Recovery is three to five days of soreness, with no anti-inflammatory drugs afterwards — only what the treating physician prescribes. Where improvement occurs it is generally described between four and six months.
One last piece of honesty. Some patients do not improve. And neither option rebuilds a joint that has already reached the point of replacement — a proper assessment should tell you that too, even when the answer is that neither treatment is for you.
- Start from your imaging: what is damaged, and for how long.
- If you are offered PRP, ask which preparation it is. The best one depends on the stage of the disease.
- Expect three to five days of soreness, no anti-inflammatories afterwards, and improvement, where it occurs, between four and six months.
Network meta-analyses of 43 and 79 randomised trials in knee osteoarthritis rank both PRP and mesenchymal stem cells above placebo and hyaluronic acid, with stem cells stronger for pain and leukocyte-poor PRP stronger for function and tolerability. Neither rebuilds a joint that has reached the point of replacement.
- Intra-articular injections of platelet-rich plasma, adipose mesenchymal stem cells, and bone marrow mesenchymal stem cells associated with better outcomes than hyaluronic acid and saline in knee osteoarthritis · Arthroscopy, 2021
- The efficacy of intra-articular injections in the treatment of knee osteoarthritis: A network meta-analysis of randomized controlled trials · The Knee, 2021
- The efficacy of platelet-rich plasma preparation protocols in the treatment of osteoarthritis · Journal of Orthopaedic Surgery and Research, 2025
Questions
Is PRP or stem cell therapy better for knee pain?
Neither wins across the board. In the meta-analyses, adipose stem cells ranked best for pain at six months and leukocyte-poor PRP ranked best for function. Which one fits depends on what your imaging shows.
When is PRP enough?
For a mild, recent injury where the tissue is still largely intact. It is not the route for established structural damage, such as a worn meniscus or advanced cartilage loss.
Do you apply PRP on its own?
No. The cells are always the treatment. Depending on the case they may be combined with exosomes or with PRP, never corticosteroid alone and never PRP alone.
How many cells are applied?
50 million cells with exosomes for a large joint such as the knee, hip or shoulder, and 30 million for a small joint such as the ankle, wrist or elbow.
Is stem cell therapy approved by the FDA?
Stem cell therapy is not approved by the FDA, but in Colombia it is legal.