PRP (Platelet-Rich Plasma) for Joint and Tendon Pain

What is PRP?

PRP, or platelet-rich plasma, is an injection prepared from your own blood. We draw a sample just like any routine lab test, spin it in a centrifuge to concentrate the platelets, and obtain plasma loaded with growth factors. That is what gets injected into the painful joint or around the painful tendon.

The idea behind it is simple: platelets release substances involved in tissue repair. What remains under debate — and it is worth saying upfront — is how much of that translates into less pain, and for how long. The evidence is mixed and depends heavily on the indication and on how the concentrate is prepared.

Let me be clear from the start: PRP is not a cure, and it does not regenerate cartilage that is already worn away. The osteoarthritis is still there. What it can do, in some well-selected patients, is reduce pain for a period of time. If someone promises to "rebuild your knee" or talks about miracles with stem cells, know that the evidence does not support that. I would rather offer you realistic expectations, even if they are more modest.

Which kinds of pain is it used for?

PRP has been studied mainly in two scenarios. In neither does it replace a proper diagnosis: before proposing it, we evaluate your case with an examination and the appropriate imaging.

Mild to moderate knee osteoarthritis

This is the most common indication. It is considered when pain from mild to moderate osteoarthritis is not controlled with physical therapy, weight loss and the usual medication. This is where the evidence is most debated, and further down I lay it out exactly as it is.

Tendinopathies that will not settle

Some tendon pain conditions that become chronic and do not improve with rehabilitation can be considered for PRP. The shoulder tendon (rotator cuff), tennis elbow and certain tendons of the knee are examples. Here too, results vary depending on the tendon.

What is the day of the procedure like?

It is an outpatient procedure. It is done in the office or in a minor procedure room, and you walk out the same day.

• First we draw a small amount of blood, just like a routine lab test.
• The blood is processed in a centrifuge for a few minutes to separate and concentrate the platelets.
• The injection is done with local anesthesia. In most cases I use ultrasound guidance to deposit the plasma exactly where it needs to go, inside the joint or alongside the tendon.
• The procedure itself takes only a few minutes. Depending on the protocol, more than one injection may be planned, spaced weeks apart.

It requires no hospital stay and no general anesthesia. Some soreness at the injection site for a day or two is common; that is expected.

What to expect: the evidence, unvarnished

Here I have to be honest, because this is where the evidence is most uneven and worth looking at closely.

In knee osteoarthritis

The most rigorous study available, a placebo-controlled trial published in JAMA in 2021 (RESTORE, 288 patients followed for one year), found no difference between PRP and a saline injection — neither in pain nor in cartilage measured by MRI. That is an important result, and I am not going to hide it.

At the same time, a 2025 meta-analysis pooling 18 trials did find clinically meaningful improvement with PRP over placebo at 3 and 6 months, with an interesting detail: the benefit appeared mainly with high platelet-concentration preparations, while low-concentration ones showed no clear advantage for pain. Other studies attribute better results to PRP than to hyaluronic acid in some patients.

What do I take from all this? That PRP can help some people with knee osteoarthritis. The effect is modest and temporary, and probably depends on how the plasma is prepared. What it does not do, in any case, is repair the joint. It is not for everyone, and it is not the first option.

In tendinopathies

Mixed as well. A large trial in JAMA on Achilles tendinopathy showed no benefit of PRP over a sham injection. In contrast, an Argentine study from the Hospital Italiano de Buenos Aires in refractory supraspinatus tendinopathy in younger patients (ages 18-50) found that PRP showed better results than corticosteroid at 12 months for pain and function. That is why the decision is case by case: it matters which tendon it is, how long it has been hurting, and what you have already tried.

Where is it performed? Locations in Buenos Aires

I see patients at two locations: Hepta, in San Isidro (Av. Fondo de la Legua 577, northern Buenos Aires suburbs) and CIAREC, in Villa Urquiza (Av. Monroe 4770, Buenos Aires City). In the consultation we assess your case and coordinate where and when to perform the procedure. I see patients from across the northern suburbs of Greater Buenos Aires and from Buenos Aires City. Phone: (011) 5895-3260.

Insurance coverage

PRP is not always covered by Argentine private health plans (prepagas) or union-based health plans (obras sociales), and coverage varies by plan and indication. In many cases it is handled as a self-pay procedure. In the consultation I explain clearly how it works out under your coverage — no surprises — before any decision is made.

When to seek a consultation and next steps

It makes sense to seek a consultation if you have knee osteoarthritis pain or tendon pain, have already done the baseline treatment (physical therapy, medication, lifestyle changes) and it still limits you. PRP is one of the possible tools — not the only one and not the first — and it is always assessed as part of a broader plan.

In the consultation we review your diagnosis and imaging, look at what you have already tried, and I tell you frankly whether PRP has a reasonable chance of helping in your case or whether something else makes more sense. If we go ahead, I explain the protocol, how many injections, what to expect and how we track the result over time.

My rule is simple: I offer PRP when I believe it can add something concrete in your case, not because it is fashionable. If I think it will not help you, I will say so. I would rather you leave with an honest expectation than with a promise that later goes unfulfilled.

Dr. Mauricio Casarsa

Anesthesiologist. Postgraduate training in Pain Medicine and Interventional Pain Management (UBA — Fundación Dolor; UNLP — CAIDBA). Staff physician at Hospital Alemán de Buenos Aires.

MN 137.756 (Argentine medical license) · San Isidro · Villa Urquiza