Why PRP works for some people and not others

RESPONDERS

Two people get the same injection into the same joint at the same grade, and one improves for a year while the other reports nothing. That difference is not random, and most of it is knowable before the needle.

Three things vary, and only one is the treatment

The first is what was in the syringe. Preparation systems differ in platelet yield by several fold, in leukocyte content by design, and in whether the product is activated. Two clinics can hand you the same word and deliver materially different biology, and the dose that reaches the tissue tracks with outcome. The leukocyte question alone changes the direction of the effect in some tissues.

The second is the target. A joint injected without knowing which structure generates the pain is a coin toss dressed up as a procedure. Facet pain is a diagnosis you make with a needle, not a scan, and a disc that hurts and a disc that looks bad are not the same disc.

The third is you — and this is the one nobody discusses, because it is the least marketable and the most consequential.

The terrain does the healing

PRP does not repair anything. It signals; your cells repair. So the capacity of those cells is the ceiling on the result, and that capacity is measurable.

Type 2 diabetes changes tendon homeostasis directly: collagen cross-linking, matrix turnover and the cellular response to injury are all altered, and orthopedic outcomes across procedures are consistently worse in poorly controlled disease. Insulin resistance short of diabetes moves the same levers more quietly. Add smoking, which impairs the microvascular supply the repair depends on, and chronic sleep restriction, which suppresses the largely nocturnal repair signaling, and you have most of the variance that gets attributed to the injection.

None of that is a lecture about discipline. Access to food, shift work and the cost of both are doing a share of it, and a plan that ignores that is a plan for somebody else. But it is the reason we ask for bloodwork before we quote you a probability. Why a pain clinic asks to see your bloodwork.

What we look at before agreeing to treat

• HbA1c and fasting insulin. Not to disqualify you — to know what we are working with, and to tell you honestly what it does to the odds.
• Vitamin D and thyroid function, both of which affect connective-tissue repair and both of which are correctable.
• What you are taking. Sustained anti-inflammatory use around the treatment window works against the mechanism you are paying for.
• Prior corticosteroid exposure at the site, and how recent. The two are not interchangeable and the sequence matters.
• What the tissue actually is. A cuff tear with fatty infiltration and a tendinopathy are different problems. The tear is only half the diagnosis.

The uncomfortable version

I spent years attributing variable results to the preparation, because that is the part a physician controls and the part that is interesting. It is real, and it is not the largest term. The largest term is the metabolic state of the person on the table, and I was not measuring it.

Which means the most useful thing you can do before a regenerative treatment is not choosing a clinic with a better centrifuge. It is arriving with the terrain in better shape than it is now, and there is usually more room there than anyone has told you.