RESUMEN
BACKGROUND: The conservative management of lateral epicondylitis is known to be a difficult-to-treat annoying condition. A treatment with platelet-rich plasma (PRP) is often performed, but its efficacy remains controversial. METHODS: This study is a single-center, randomized double-blind controlled trial, preceded by a case series. All the 232 planned patients of the case series will undergo an up-to-date comprehensive rehabilitation program, including focused extracorporeal shock waves therapy. This rehabilitation program is expected to have a maximum success rate 75%. It is therefore aimed to allocate a minimum of 58 patients with rehabilitation failure into the 1:1 randomized trial. Stratification is planned on age and lesion pattern. The masking will be quadruple (Participant, Care Provider, Investigator & Outcome Assessor). The patients will undergo an ultrasound (US)-guided needling combined with either PRP (intervention group) or saline (control group). The primary endpoint will be the pain improvement from baseline (month 0) at 3 months on a 0-10 visual analog scale (VAS) during a maximal strength isometric contraction of the extensor carpialis brevis muscle. The main secondary endpoints will include the rehabilitation success rate and improvements from baseline at 3, 6, and 12 months of the following outcomes: (i) Single Assessment Numeric Evaluation (SANE) score, (ii) Patient-Rated Tennis Elbow Evaluation (PRTEE) score, (iii) maximal grip strength on Jamar test, and (iv) the ultrasonographic evaluation of the US of the epicondylar tendons. DISCUSSION: The study results will provide insight into the effect of PRP as adjuvant therapy to tendon fenestration, and may contribute to identify the best preceding and concomitant rehabilitation protocol. TRIAL REGISTRATION: ClinicalTrials.gov NCT03987256. Registered on 20 August 2019.