Introduction
Lateral epicondylitis, or “tennis elbow,” is a common elbow condition. It primarily affects individuals whose activities involve strong gripping or repetitive wrist actions, typically using the dominant arm. The cause is believed to be due to lesions caused by mechanical overloading and abnormal microvascular responses at the origin of the wrist and finger extensor muscles on the lateral epicondyle of the elbow.
Traditional treatments include rest, NSAID medications, bracing, physical therapy, Botox injections, corticosteroid injections, or surgical procedures when the above measures fail. Shock wave therapy [link to shock wave therapy for elbow] is a newer treatment option that may benefit lateral epicondylitis. Additionally, platelet-rich plasma (PRP) has been proposed as an ideal alternative to traditional treatment options.
PRP releases high concentrations of growth factors into the injured tissue, enhancing wound healing, bone healing, and tendon healing. It also has antimicrobial properties and may help prevent infections (Everts, 2007).
The Study
The authors previously published the results of a 12-month double-blind randomized trial [link to https://journals.sagepub.com/doi/abs/10.1177/0363546510397173] that compared the efficacy of PRP versus corticosteroids for the treatment of lateral epicondylitis. The outcome measures were pain and function. The present study is an extension of the original study with outcomes at two years for the 100 patients enrolled in the original study. All patients in this study had symptoms lasting more than six months to control for the effects of natural recovery, which mostly occurs in the first six months after injury. Groups were similar in characteristics except that at baseline, the PRP group reported significantly greater functional disability than the corticosteroid group.
A single non-activated PRP or corticosteroid injection was administered into the common extensor tendon using a peppering technique, in which the needle is inserted at the tender area, then sequentially injecting the medication, withdrawing, redirecting, and reinserting all without emerging from the skin. There was no control group because this study was conducted in the Netherlands, where the Institutional Review Board does not allow control groups.
Results
The corticosteroid group reported a decrease in pain at four weeks post-treatment, which plateaued for eight weeks. The pain level then increased at 26 weeks but remained below baseline levels. In contrast, the pain scores of the PRP group significantly improved at each follow-up point, including the two-year follow-up. Overall, the difference in pain level between the two groups was significant. Sixty of the 100 patients reported a 25% reduction in pain without reintervention at two years. Of these successful treatments, 39 were in the PRP group, and 21 were in the corticosteroid group. Eleven patients deteriorated, with nine of these receiving a corticosteroid and two receiving PRP.
Regarding function/disability scores, the corticosteroid group reported improved function at four weeks with a significant additional increase at eight weeks. At 12 weeks, function declined further at 26 weeks and remained declined at the two-year point. In contrast, the PRP group showed steady improvement in function at each assessment point, including two years. Symptom scores for both groups were comparable to the functional disability scores. Fifty-six of the 100 patients reported a 25% improvement in function and symptoms without reintervention during the two-year period. Of the successful treatments, 37 were in the PRP group, and 19 were in the corticosteroid group. Several patients deteriorated, of which 23 received corticosteroids, and seven received PRP.
There were six reinterventions in the PRP group: three patients required surgery, and three received a corticosteroid injection. There were 14 reinterventions in the corticosteroid group: six surgeries, one patient received corticosteroids every three months, and seven patients crossed over to the PRP intervention. The seven crossover patients experienced significant improvement in pain and function after receiving PRP. Patients who received surgery or reinjection with corticosteroids did not experience improvement in pain or function.
Adverse Effects
No adverse effects were reported with PRP, except for initial worsening of pain for one to two weeks due to activation of the inflammation cycle.
Conclusion
The corticosteroid group experienced initial improvement, which then declined toward baseline over time, while the PRP group showed steady improvement with time. It is noteworthy that the PRP group reported worse pain and disability scores at baseline than the corticosteroid group. This observation strengthens the conclusion that PRP is more effective for long-term pain relief and tissue recovery than traditional steroid treatments for lateral epicondylitis. [link to steroid decreases stem cell counts at tendons]
References
Gosens, T., Peerbooms, J., van Laar, W., et al. (2011). Ongoing positive effect of platelet-rich plasma versus corticosteroid injection in lateral epicondylitis. AJ Sports Medicine, 39(6):1200–1207.
Everts, P., Overdevest, E., Jakimowicz, J., et al. (2007). The use of autologous platelet-leukocyte gels to enhance the healing process in surgery. Surg Endosc, 21(110):2063–2068.
