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PRP Injections: 3 Critical Mistakes You Must Avoid At All Costs

There are three critical mistakes that can undermine the effectiveness of PRP injections and these mistakes directly translate into disappointing outcomes. But here’s the good news, each mistake is completely preventable. I’m going to reveal what these common pitfalls are and how to avoid them. The goal is to ensure you achieve the best possible outcomes from your platelet rich plasma treatments.

Clinical trials continue to show that PRP injections consistently outperform many treatments for osteoarthritis, tendon tears, and tendinopathies. But it’s also important to understand that not all PRP is the same. There are many variables that can hinder their success and lead to poor outcomes. So let’s go through the top 3 mistakes people often make with PRP treatments.

Mistake number one is platelet dosing. Just like with any other medication, platelet rich plasma has a dose response curve. This means if we don’t administer enough platelets, you won’t see meaningful improvements. We learned this lesson from the RESTORE trial which made headlines in JAMA which is a very highly read and highly respected medical journal. 

The study compared PRP injections to placebo for the treatment of knee osteoarthritis. They concluded that platelet rich plasma injections did NOT result in significant differences in symptoms at 12 months and that their findings do NOT support the use of PRP for knee osteoarthritis.

So even though the trial was well designed and well executed, it had a fatal flaw. The study used commercial kits called RegenLab BCT kits which, according to the manufacturer, involves a 10 cc blood draw and concentrates platelets to 1.6 times baseline levels for around 1 to 2 billion platelets. For comparison a high dose PRP kit would start with a 60 cc blood draw which is 6 times the amount of blood and platelets that is then processed and concentrated for treatment.

Now this next part is really important. The true definition of platelet rich plasma is a platelet concentration of at LEAST 3 to 4 times higher than the baseline levels in whole blood. Therefore, the product used in the RESTORE trial, which was only a 1.6 times concentration, did not even qualify as platelet RICH plasma. And because they severely underdosed their treatment, this explains why the study found PRP injections were no more effective than placebo.

The reason this matters to you is because most orthopedic surgeons and sports medicine physicians and clinicians who offer PRP do not understand this yet. The vast majority of providers use similar low dose commercial PRP kits for processing because of cost. And the main reason why they do this is because they assume all PRP kits are the same and so why wouldn’t they go for the cheapest ones to minimize pricing. 

So whenever I see a patient who has tried PRP in the past but did not notice improvement, the first thing I ask is how much blood was drawn. Almost always, only a small volume of blood was used, confirming my suspicion that they received a low dose plasma injection rather than true platelet RICH plasma.

Now let’s contrast all of that with high dose PRP. This study started with a 50 cc blood draw, and after processing, ended up with a platelet concentration of 4.3 times over whole blood. Their platelet counts ended up being around 4 to 5 billion platelets in each injection. The results of the study showed that not only was PRP superior to placebo for pain, function, and overall arthritis symptoms, but 3 high dose PRP injections significantly decreased the levels of inflammatory markers in the knee joint and slowed the progression of arthritis by up to 50% when compared to placebo. 

Other studies report the same results when using high dose PRP. For example, this one writes that correct PRP dosing is critical for long term clinical efficacy. They started with a 60 cc blood draw and ended up with around 10 billion platelets per PRP injection. They argue that PRP with absolute counts of 10 billion platelets is crucial to provide significant chondroprotective effects and symptom relief for those with knee osteoarthritis.

We see the exact same effects when it comes to soft tissue injections. Platelet dosing is critical to ensure optimal outcomes when treating partial tendon tears as well as tendinopathies. This review found that studies using higher platelet dose resulted in significantly better outcomes than the studies that used low dose PRP. 

So, here’s what you need to do to prevent a dosing error. Number 1: You MUST ask your provider how much blood will be drawn for your PRP treatment. This will give you a good estimate of how many platelets will end up in your injection. The more blood that is drawn, the higher the dose of platelets you are getting. 

This table is a guide that estimates how many platelets will be in a PRP sample using the blood draw as a starting point. Large joint injections such as knees and hips require a 50 or 60 cc blood draw to get around 10 billion platelets. Smaller targets require less platelets but still need around 5 billion, which is about a 30 cc blood draw. You must ask if the commercial kits that your healthcare provider is able to process these larger volumes. 

PRP injection volume (cc)

Blood draw (1 tube is 8-10 cc)

Approx final concentration (50-80% capture)

Approx platelet count (in billions)


10 cc




20 cc




30 cc




60 cc




80 cc




120 cc



Number 2: a larger initial blood draw does NOT guarantee that the centrifuge process will efficiently recover platelets. Some single spin protocols get less than 50% platelet recovery which means you still aren’t getting a high dose. Double spin centrifuge protocols have significantly higher platelet recovery which translates into higher dose and better outcomes. In my experience, most orthopedic providers use low cost single spin PRP kits that can handle only up to 20 cc of total volume. Again, be warned. These low cost kits have NOT been shown to be better than placebo treatments. 

Lastly number 3: once you’ve ensured you're getting high-dose PRP and the processing is ideally done with a double spin centrifuge protocol, it's crucial to inject the entire sample into a single spot. I've encountered numerous cases where the sample was split into five syringes and dispersed around the intended site. Think about this. If the target needs 10 billion platelets, and you divide that into 5 syringes, you are now injecting 2 billion into each area. This means you are back to injecting low dose PRP and this will result in suboptimal outcomes. The entire 10 billion platelets must be delivered directly to the desired target.

This brings us to mistake number two, which is injection technique. Imaging guidance is essential for platelet rich plasma injections. It doesn’t matter how many years of experience your doctor has. Even the most skilled and seasoned orthopedic providers can miss their injections. And you certainly don’t want to be the one that they miss. 

To illustrate my point, here is a comparison of accuracy for common injections using ultrasound guided and landmark based techniques. The data speaks for itself. Landmark based accuracies often range in the low to mid 60’s. Accuracy with ultrasound guidance is almost always guaranteed. The last thing you want to do is undergo a medical procedure only for your health care provider to do a landmark based injection and then miss the target.

Body Area

Ultrasound Guided Accuracy

Landmark Based Accuracy

Glenohumeral joint



Acromioclavicular joint



Biceps tendon



Elbow joint



Hands and wrist joints



Hip joint



Knee joint



Foot and ankle joints



Moreover, when it comes to PRP injections for soft tissue conditions like partial tendon tears and tendinopathy, accurate placement of platelets is essential for success. The most dependable way to ensure that the PRP reaches the right spot is by imaging guidance. Don't let anyone convince you that they can simply 'feel' the problem area and accurately inject the PRP. They don’t have x-ray vision and they can’t ‘feel’ where a tear is. That's not how it works.

Clinical trials demonstrate that imaging guidance results in superior outcomes. Researchers from this study performed ultrasound-guided tendon debridement followed by either PRP injections or a saline placebo. Remarkably, 87% of the PRP-treated group experienced a reduction in tear size by the six-month mark with 79% achieving complete healing. On the other hand, the saline placebo group showed just 32% of tears decreasing in size with only 21% reaching full healing.

These results just aren’t possible with the old school method of using landmark based injection techniques. To replicate these results, your procedure must be done with imaging guidance. So here’s what you need to do. You need to ask if your PRP injection will be done with imaging guidance. If you get pushback, consider finding another provider who has the technical skills to ensure correct placement. 

The last mistake when it comes to PRP injections is taking NSAID medications. Common medications in the NSAID class of drugs include aspirin, ibuprofen, naproxen, diclofenac, and indomethacin. Platelets release growth factors that are crucial for the healing process. NSAIDs, by their mechanism of action, inhibit the function of platelets, potentially reducing the effectiveness of the growth factors that PRP therapy relies on to initiate tissue repair.

This study found that daily use of low dose aspirin reduced vascular endothelial growth factor, platelet derived growth factor, and TGF beta-1 expression in platelet rich plasma. This means that if you take NSAIDs prior to your PRP procedure, your platelets will not be able to initiate the cascade of growth factor release necessary for a proper response. 

In addition, while chronic inflammation can be harmful, acute inflammation is an essential part of the body's natural healing process. NSAIDs work by reducing inflammation, but in the context of PRP therapy, this might not always be beneficial. The initial inflammatory response following a PRP injection is considered a crucial step in the healing process, as it signals the body to start repairing the injured tissue. By dampening this response, NSAIDs could hinder the effectiveness of PRP therapy.

This is exactly what we see in animal studies. Rats given NSAIDs after orthobiologic injections had significantly worse arthritis when compared to rats that got treatments without NSAIDs. Taking these medications after injections inhibits the release of growth factors which results in worse outcomes. 

Now there are some studies to suggest that selective NSAIDs such as meloxicam and celecoxib may not significantly impair the healing process, but the evidence is still inconclusive. In my opinion, if you are going to get PRP, you might as well try to come off of all NSAIDs to minimize disruption to your PRP. 

So here’s what I recommend: stop taking NSAIDs at least 1 week prior to your PRP injection. Continue to hold them for at least 2 weeks after the treatment and ideally up to 6 weeks. The longer you can hold off taking NSAIDs after a biologic treatment, the better the outcomes.

In summary, the three most common mistakes made with PRP injections are incorrect platelet dosing, not getting injections with imaging guidance, and not stopping NSAID medications.


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