PRP for Tennis Elbow: What’s the “Secret Sauce”?

This post comes from Fred Nelson, MD, an orthopaedic surgeon in the Department of Orthopedics at Henry Ford Hospital and a clinical associate professor at Wayne State Medical School. Some of Dr. Nelson’s tips go out weekly to more than 3,000 members of the Orthopaedic Research Society (ORS), and all are distributed to more than 30 orthopaedic residency programs. Those not sent to the ORS are periodically reposted in OrthoBuzz with the permission of Dr. Nelson. 

There are many suggested applications for platelet-rich plasma (PRP), including tendon repair, osteoarthritis, and other musculoskeletal conditions. However there is considerable controversy in the absence of convincing evidence about the optimal mix and concentration of white blood cells and platelets in PRP, and the most clinically effective nature and quantity of constituent cytokines or other biochemical agents in PRP.

Despite these lingering questions, PRP is commonly used to treat lateral epicondylitis (LE), commonly called “tennis elbow.” As with its other applications, the clinical use of PRP for painful tendons has received much attention, but its efficacy remains controversial.

To continue investigating the clinical effects of PRP and its individual components, researchers recruited 156 patients with LE and randomly divided them into those treated with a single injection of 2-mL autologous PRP and those who received only physical therapy without injection.¹ Both groups used a tennis elbow strap and performed stretching and strengthening exercises for 24 weeks, at which point pain and functional improvements were assessed using the visual analog scale (VAS), Modified Mayo Clinic Performance Index for the elbow, and MRI. Levels of platelet-derived growth factor-AB (PDGF-AB), PDGF-BB, transforming growth factor-β (TGF-β), vascular endothelial growth factor, epithelial growth factor, and interleukin-1 β in the PRP were measured for statistical correlation with clinical scores.

At 24 weeks, all pain and functional variables—including VAS score, Mayo Clinic performance scores, and MRI grade—improved significantly in the PRP group, relative to the noninjection group (p < 0.05). The TGF-β level in the PRP significantly correlated with Mayo Clinic performance score and MRI grade improvement.

The PRP level of TGF-β appears to be important in tendon healing, but future studies will be required to determine the best relative concentrations of white blood cells and platelets that deliver specific cytokines such as TGF-β. However, these results help identify a viable protocol for measuring PRP efficacy in tendinopathies.

Reference

1. Lim W, Park SH, Kim B, Kang SW, Lee JW, Moon YL. Relationship of cytokine levels and clinical effect on platelet-rich plasma-treated lateral epicondylitis. J Orthop Res. 2018 Mar;36(3):913-920. doi: 10.1002/jor.23714. Epub 2017 Sep 20. PMID: 28851099