Am I a candidate? What the trials actually enrolled

Who was actually in these studies

A 2025 systematic review in Frontiers in Medicine catalogued the eight placebo-controlled trials of cell therapy for knee osteoarthritis. The population they enrolled is more useful to a prospective patient than most people realise:

Two things stand out. First, the severity range is wide: these were not only early, mild cases. Trials enrolled patients across grades 2 to 4, and one included grade 1. Second, the mean BMI in several trials sat in the overweight-to-obese range — a population often assumed to be excluded from this kind of study.¹

The clearest exclusion in the literature

The exclusion criterion that appears consistently is prior knee replacement or other major surgery on that same knee. It is worth knowing this early: if you have already had the joint replaced, the published evidence does not speak to your situation at all, and any clinic implying otherwise is going beyond what exists.

Beyond that, individual trials applied their own criteria — active infection, certain cancers, uncontrolled systemic disease, pregnancy, and specific medications are common exclusions in this kind of research. This is exactly the territory a proper assessment covers, and exactly why it cannot be done from a web page.

What is still being argued about

The honest caveat is that which patients respond best remains genuinely unsettled. There is not yet a validated way to predict, from your file alone, how much benefit you would get.

What the pooled analyses have started to separate is the treatment side rather than the patient side. A 2024 review of 18 trials and 1,174 patients found in subgroup analysis that adipose-derived cells outperformed bone marrow and umbilical cord sources, and that allogeneic preparations outperformed autologous ones.² The authors were explicit that heterogeneity was high and that these are signals, not settled conclusions.

That matters for a practical reason: it means the differences between clinics are not marketing differences. Cell source and preparation are among the variables the literature is actively trying to pin down, so asking a clinic what it uses and why is a substantive question, not a formality.

What a real assessment looks at

A candidacy review is mostly a records exercise. What a physician is trying to establish:

• What is actually happening in the joint — from imaging, not from symptoms alone. Pain and structural damage correlate imperfectly.
• Where you are in the disease and how quickly it has moved.
• What has already been tried, and what happened. Prior injections and surgery change both the picture and the options.
• What else is going on medically — other conditions, medications, anything that changes the risk side of the equation.
• Whether something else should be addressed first. Sometimes the right answer is a different treatment, or the same treatment later.

How to find out, in the order that saves time

• Get your imaging from the last twelve months — the images themselves, not just the radiologist's report.
• Write down the history: how long, what makes it worse, what you have tried, what helped and for how long.
• List medications and supplements, with doses.
• Ask your own physician for their assessment first. A second opinion is more useful when the first is on record.
• Have your records reviewed and ask for the answer in writing, with the reasoning — including the reasoning for a no.

This costs you the time it takes to gather documents. It is the only way to replace a guess about yourself with an answer about yourself.

See how a records review works at Medgenik →