Why Do Studies Show Different Results for PRP Injections?

Patients looking for relief from the chronic pain of osteoarthritis (OA) are generally offered pain medication, surgery, and physical therapy. More and more are being offered platelet-rich plasma (PRP) injections. As to whether the injections work, the jury is still out. Studies show different results, making it difficult to take a definitive position either way.

Competing Study Results

One of the more recently released studies took place in Australia over a two-year period from August 2017 to July 2019. With the help of 288 participants, researchers were able to determine that PRP injections do not perform any better than placebo for either reducing pain or improving joint structure.

On the other hand, a 2014 study out of the Netherlands determined just the opposite. That study was a meta-analysis of previous PRP studies utilizing both randomized and non-randomized study models. Researchers determined that patients receiving PRP injections reported less pain and greater joint function compared to placebo patients.

So why the disparity? Furthermore, why so much disparity among so many studies? The two mentioned here are not the only studies on this topic. Researchers have been looking at regenerative medicine for years. So far, they have not come up with a concrete explanation as to why study data doesn’t agree.

Patients React Differently

The first thing to consider is that patients react differently to all kinds of treatments. However, regenerative medicine is a bit different than traditional Western medicine. For example, when a patient visits Lone Star Pain Medicine to receive PRP injections for OA, doctors at the Weatherford, TX clinic aren’t treating the actual joint. They are encouraging the body to repair the joint.

This is in stark contrast to prescribing pain medications or relying on joint replacement surgery. Both of the traditional treatments have a well-defined impact on the physical structure of the affected joint. PRP injections have a more indirect impact. Thus, it would be normal to see significant disparities in how patients respond.

Of course, this does not explain the differences between PRP injections and placebo. But other things could. For example, preparation method and injection site choices both affect treatment outcomes.

Utilizing Optimal Treatment Methods

Those who stand behind PRP injections insist that there are better and worse ways to do things. They tend to utilize optimal treatment methods that start with how blood plasma is prepared prior to injection. The goal of preparation is to end up with a plasma product containing an extremely high concentration of platelets and growth factors.

The higher the concentration, the more effective the growth factors are. Therefore, some of the study disparities could be the result of different preparation methods.

As for injection sites, some doctors tend to use imaging equipment to determine the best injection sites. Those choosing not to may do so under the assumption that any injection site close to the affected joint is suitable. But this may not be true. And if it turns out that injection site choice does significantly impact outcome, it could explain study disparities.

Anecdotal Evidence Is There

As things currently stand, research data cannot conclusively say whether PRP injections work as an OA treatment or not. There are too many disparities in study results. Meanwhile, the anecdotal evidence in support of PRP injections is there. Significant numbers of patients who receive the injections say they work.

As the scientific community continues to study regenerative medicine, they should not discount anecdotal evidence. Reporting pain is subjective regardless of the methodology used to gather data. Therein may lie the key to understanding study disparities.