Platelet-rich plasma has become a popular treatment in sports medicine, orthopedics, and podiatry. But what exactly is PRP, and how much evidence do we actually have that it works?
In this episode, we break down the science, clinical applications, and controversies surrounding PRP.
What Is PRP?
PRP is a concentrated preparation of a patient's own blood containing a higher concentration of platelets than normal blood.
Platelets do more than help form blood clots. They contain numerous signaling proteins and growth factors that participate in tissue repair, inflammation, angiogenesis, cellular recruitment, and tissue remodeling.
How Is PRP Made?
The process generally involves:
- Drawing the patient's blood
- Processing the blood, usually with centrifugation
- Separating blood components
- Concentrating platelets
- Removing or retaining varying amounts of white blood cells and red blood cells
- Injecting the resulting preparation into the target tissue
Importantly, PRP is not one standardized product.
Different systems can produce substantially different platelet concentrations and cellular compositions.
What's Actually in PRP?
Depending on the preparation, PRP can contain:
- Platelets
- Plasma
- Growth factors
- Cytokines
- White blood cells
- Fibrin
- Small amounts of red blood cells
We discuss why leukocyte-rich and leukocyte-poor PRP may behave differently and why the optimal formulation remains uncertain for many conditions.
The Science Behind PRP
Activated platelets release biological mediators that can influence:
- Fibroblast activity
- Collagen production
- Angiogenesis
- Inflammatory signaling
- Cellular migration
- Extracellular matrix remodeling
- Tissue repair
But biological plausibility doesn't necessarily equal clinical effectiveness.
One of the major themes of this episode is the difference between mechanistic evidence and patient outcomes.
PRP in Orthopedics
We discuss the evidence surrounding PRP for:
Knee osteoarthritis
PRP has some of the more encouraging evidence in this area. Several randomized trials demonstrate improvements in pain and function, although the magnitude and durability of benefit remain debated.
Rotator cuff tendinopathy
Evidence is mixed, but some newer studies suggest PRP may provide greater longer-term improvement than corticosteroid injections.
Tennis elbow
Despite a strong biological rationale and widespread clinical use, recent placebo-controlled evidence has not demonstrated a convincing benefit over placebo.
Achilles tendinopathy
This is one of the most important examples discussed in the episode. Despite a compelling biological rationale, recent randomized placebo-controlled studies have failed to demonstrate a meaningful advantage of PRP over placebo.
PRP in Foot & Ankle Medicine
We examine potential applications for:
- Plantar fasciopathy
- Achilles tendinopathy
- Peroneal tendinopathy
- Posterior tibial tendon disorders
- Selected ligament injuries
- Osteoarthritis
- Selected postoperative or surgical applications
The evidence varies considerably between conditions.
PRP for Plantar Fasciopathy
Some studies suggest PRP may provide longer-term improvement compared with corticosteroid injections.
However, comparisons against corticosteroid don't answer the same question as comparisons against placebo.
The key question remains:
Does PRP itself provide a clinically meaningful benefit beyond the effects of the injection and rehabilitation?
PRP for Achilles Tendinopathy
Despite being one of the most popular applications for PRP, high-quality placebo-controlled evidence has been disappointing.
Recent meta-analyses have found no significant improvement in pain or function compared with placebo.
This illustrates an important lesson:
A treatment can have a highly plausible biological mechanism without producing a meaningful clinical benefit.
Why Placebo-Controlled Studies Matter
Injection studies are particularly susceptible to placebo effects.
Patients receive:
- A physician consultation
- A procedure
- A needle
- Post-treatment instructions
- Often physical therapy
- And the expectation that treatment will help
Therefore, PRP needs to be compared against an appropriate control—not simply against doing nothing.
Statistical Significance vs. Clinical Significance
A statistically significant result doesn't necessarily mean a patient feels substantially better.
We discuss the concept of the minimal clinically important difference, which asks whether the magnitude of improvement is large enough for patients to actually notice and value.
Why PRP Studies Often Disagree
One of the major problems with the PRP literature is lack of standardization.
Studies may differ in:
- Platelet concentration
- Leukocyte concentration
- Red blood cell contamination
- Activation method
- Injection volume
- Number of injections
- Injection technique
- Ultrasound guidance
- Rehabilitation protocols
- Patient population
- Severity of disease
- Follow-up duration
So when someone says, "Studies show PRP works," an important follow-up question is:
Which PRP? For which condition? Compared with what?
PRP vs. Corticosteroid
Corticosteroids can provide relatively rapid symptom relief through their anti-inflammatory effects.
PRP is intended to influence the biological environment and may have a slower onset of benefit.
For some conditions, PRP appears to provide more durable improvement than corticosteroid.
For others, the difference is minimal or uncertain.
Neither treatment should automatically be considered "better" without considering the diagnosis and evidence.
Is PRP a Stem Cell Treatment?
No.
PRP does not introduce stem cells into the injured tissue.
It uses the patient's own platelets and the biological mediators associated with them.
Does PRP Regenerate Cartilage?
This claim requires caution.
Laboratory and animal studies demonstrate potentially beneficial effects on cartilage biology.
Some human studies demonstrate improvements in pain and function.
But symptom improvement is not the same as proven regeneration of normal articular cartilage.
Clinical improvement should not automatically be interpreted as cartilage regeneration.
What Should Patients Ask Before Getting PRP?
Before undergoing PRP, consider asking:
- What is my exact diagnosis?
- What does the evidence show for PRP specifically for this condition?
- What type of PRP are you using?
- What is the platelet concentration?
- Is it leukocyte-rich or leukocyte-poor?
- How many injections will I need?
- Will ultrasound be used?
- What rehabilitation will accompany the injection?
- What improvement should I realistically expect?
- What are my alternatives?
- What will it cost, and is it covered by insurance?
The Bottom Line
PRP represents an exciting area of orthopedic and regenerative medicine.
There is legitimate science behind the concept.
There are biologically active molecules within platelets that can influence tissue healing.
But the clinical evidence is far more nuanced than many advertisements suggest.
For some conditions, PRP appears beneficial.
For others, the benefit is modest or uncertain.
And for certain conditions—including Achilles tendinopathy and tennis elbow—recent placebo-controlled evidence does not demonstrate a meaningful advantage over placebo.
The most important lesson is that PRP should be viewed as a treatment option—not a cure-all.
The right question isn't:
"Does PRP work?"
The better question is:
"Does PRP work for my specific condition, using this particular preparation and treatment protocol, and is the expected benefit worth the cost and alternatives?"
That is the conversation patients should be having with their physicians.
The content of this podcast is for educational and informational purposes only and does not constitute medical advice. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.
