Background Local injections of corticosteroid represent a standard of care for epicondylitis, albeit it may adversely impair the healing process (1). Recently, local injections of growth factors-containing platelet-rich plasma (PRP) have been proposed as a new therapeutic technique, with the aim of boosting tendon repair (2). Ultrasound guidance of intra-tendinous injections seems to optimize the technical procedure (3).
Objectives The main objective was to assess the efficacy of two local injections of PRP to treat epicondylitis of recent evolution.
Methods A prospective double-blind placebo-controlled randomized trial was conducted during 2011-2012. Inclusion criteria were recent epicondylitis (pain≤3 months), confirmed by MRI and/or ultrasound and written informed consent. Exclusion criterion was previous corticosteroid infiltration. Two ultrasound-guided injections were performed at 4 weeks interval of either PRP (ACP®, Arthrex) or saline solution. Patients were monitored by an independent clinical evaluator blinded to the treatment at baseline, 1, 3, 6 and 12 months follow-up. The primary evaluation criterion was the relative improvement from baseline to 6 months in pain score (PS) on visual analog scale (0-10). Secondary criteria were the assessment of pain (yes/no) on isometric contraction of the second radial and of the extensor digitorum communis, the Roles-Maudsley score (1 to 4), the proportion of asymptomatic patients (PS ≤1) at 6 and 12 months follow-up and the proportion of patients with persistent pain (PS>2) at 12 months follow-up. Based on a sample size calculation, 21 patients in each group were needed.
Results Fifty patients were included, 25 in each group, 34 men/16 women, mean age 47±9.2 years in the ACP group and 46.4±8.6 years in the control group. Six patients dropped out of the study between baseline and 6 months, 3 in each arm. At 6-month follow-up, no statistically significant difference was found between groups for mean relative improvement in pain (ACP: -63.2±22.4%, control: -69.7±25.1%, p=0.24). No statistically significant difference was found for the secondary criteria. In the two groups, the pain score decreased significantly between two consecutive visits from 6.8±0.8 (PRP) and 7±1 (control) at baseline to 2.5±1.6 (PRP) and 2.1±1.6 (control) at 6 months and 1.65±1.5 (PRP) and 1.8±2.1 (control) at 12 months. At 6-month, 34% of all patients were asymptomatic and 66% at 1-year. The proportion of patients with persistent pain at 12 months was 23.8% in both groups. No adverse-effect was observed.
Conclusions The therapeutic effect of two ultrasound-guided ACP injections for epicondylitis of recent evolution (≤3 months) was not significantly superior to injections of saline, in a prospective randomized double-blind study with 12-months follow-up. The similarly favorable outcome registered in both study groups, may be linked to a stimulating role of ultrasound-guided intra-tendinous injections (“prolotherapy”) on the process of tendon repair.
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Disclosure of Interest P. Le Goux: None declared, B. Montalvan: None declared, J. Leparc: None declared, S. Klouche: None declared, P. Hardy Grant/research support: Arthrex, M. Breban: None declared