The Treatment of Lateral Epicondylitis: The Effect of Platelet Rich Plasma on Healing — A Randomized Controlled Double-Blinded Trial

The purpose of this study was to compare the effects of platelet rich plasma (PRP), whole blood and saline vehicle on the natural course of lateral epicondylitis (LE). Currently, there is no evidence that any treatment, including surgery, is better than placebo or no treatment in management of LE. PRP and autologous blood have been suggested as a potential therapy for LE showing promising results in animal tendon injury models and initial clinical series. However, after initial excitement, the treatments have failed to consistently show superiority over placebo and the conclusions in systematic reviews vary from strong evidence against to positive. Thus, the role of PRB and autologous blood injections in the management of LE remains unclear. We constructed a randomised controlled double-blinded study in which included adults whose symptoms were lasted over three months and primary conservative treatment had been tried. We excluded patients with significant systemic diseases, other concomitant upper limb symptoms and surgical treatment of the elbow. The study was carried out in Hatanpää Hospital, Tampere University Hospital, Tampere, Finland between February 2011 and April 2018. We injected PRP, whole blood or saline vehicle to the proximal insertion of the extensor carpi radialis brevis (ECRB) muscle in a parallel assignment model. We followed the patients at fourth, eighth, twelfth, twenty-sixth, and fifty-second week. The primary outcome measure was pain that was measured with a visual analogue scale (VAS). Secondary outcomes were QuickDASH (Disabilities of the Arm, Shoulder and Hand) -score and grip strength. We allocated the patients to groups in a randomised manner. We used a computer random number generator and concealed the allocation with sealed envelopes. Patients, personnel and outcomes assessors were blinded during the study. In statistical analysis, the groups were compared with each other with Kruskal-Wallis Rank Sum test. 119 patients participated to the study. 40 of them were treated with PRP, 40 with whole blood, and 39 with saline vehicle. At the baseline, median of the pain-VAS was 6.0 (p = 0.746). Pain-VAS of the PRP group decreased during the follow up being 5.0, 4.0, 4.0, 3.5, and 2.0 at fourth, eighth, twelfth, twenty-sixth and fifty-second week, respectively. Corresponding pain-VAS values were 5.0, 4.0, 3.8, 3.0 and 2.0 for the whole blood group and 5.5, 5.0, 4.0, 4.0 and 2.3 for the saline vehicle group (p = 0.40, p = 0.15, p = 0.65, p = 0.39 and p = 0.23, respectively). Secondary outcome measurements did not differ between the groups either. No complications occurred due to injections. PRP or whole blood did not show any advantage when compared with each other or with saline vehicle on the treatment of LE.