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Platelet rich plasma: The scientific evidence

Feb 17, 2024

We have already had a look at how platelet rich plasma (PRP) works (if you haven’t had a chance to read this yet, you can find it here), but now we are going to dive more deeply into the scientific evidence behind this treatment.
Randomised controlled trials (RCTs) are the gold standard study for determining if one treatment offers superior benefits over another. In these trials, patients are randomly assigned to either receive the treatment of interest or an alternative treatment, usually the standard of care or a placebo. Moreover, the patients are ‘blind’ to what treatment they are receiving. Here, we are going to look at two RCTs that investigated the use of PRP to treat knee osteoarthritis and chronic tennis elbow.

Knee osteoarthritis

A study by Bansal et al. (2021) investigated the optimal dose and concentration of therapeutic PRP required to achieve the desired physiologic efficacy. One hundred and fifty patients were enrolled in this trial, with then being randomised to either receive PRP or hyaluronic acid for their knee osteoarthritis.
The results revealed a significant improvement in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), International Knee Documentation Committee (IKDC) score*, and six-minute pain free walking distance. Besides external improvements, this trial also noted a significant decline in IL-6 and TNF-a levels in the PRP group when compared to the hyaluronic acid group at six months, both of which assist in mediating an inflammatory state (Bansal et al., 2021). If you would like to read more about the role of these cytokines in osteoarthritis, we have an additional blog post discussing just that.
Collectively, this trial, along with several others, demonstrate the efficacy of PRP, specifically with an absolute count of ten billion platelets, in achieving a long sustained chondroprotective effective in arthritis.
*The WOMAC represents an osteoarthritis index and measures a patients’ physical function, pain, and stiffness over a 48 hour period. The IKDC, on the other hand, gives an indication of a patients’ condition, containing questions on knee symptoms, overall function, and sports activities. The scoring system ranges from zero to one hundred, with zero representing the lowest level of function and the highest level of symptoms.

Chronic tennis elbow

A study by Mishra et al. (2014) evaluated the clinical value of tendon needling with PRP in 230 patients with chronic tennis elbow compared with an active control group. Patient outcomes were followed for up to 24 weeks, with the findings revealing several beneficial results at this mark. In those treated with PRP, a significant improvement of 71.5% was observed in their pain scores. Moreover, the percentage of patients reporting significant elbow tenderness notably decreased over this time. This demonstrates the clinical efficacy of PRP in the treatment of chronic tennis elbow on a larger scale (Mishra et al., 2014).

References

Bansal, H., Leon, J., Pont, J. L., Wilson, D. A., Bansal, A., Agarwal, D. & Preoteasa, I. 2021. Platelet-rich plasma (PRP) in osteoarthritis (OA) knee: Correct dose critical for long term clinical efficacy. Scientific Reports, 11, 3971. Mishra, A. K., Skrepnik, N. V., Edwards, S. G., Jones, G. L., Sampson, S., Vermillion, D. A., Ramsey, M. L., Karli, D. C. & Rettig, A. C. 2014. Efficacy of platelet-rich plasma for chronic tennis elbow: a double-blind, prospective, multicenter, randomized controlled trial of 230 patients. Am J Sports Med, 42, 463-71.