BackgroundStudies evaluating the results of platelet-rich plasma (PRP) for the treatment of rotator cuff tendinopathy (RCT) have demonstrated conflicting results and have been confounded by small patient samples, the absence of a control group, the combined analysis of isolated tendinopathies and rotator cuff tears, insufficient reporting of PRP preparations, The purpose of this study was to perform a randomized controlled trial comparing platelet-rich plasma (PRP) with standard corticosteroid (CS) injections in providing pain relief and improved function in patients with rotator cuff tendinopathy. MethodsThis was a double-blind RCT at a single center. We evaluated patients between 18 and 50 years old who had both a clinical and magnetic resonance (MRI) diagnosis of supraspinatus tendinopathy refractory to conservative treatment. A total of 50 patients received PRP treatment, whereas 50 patients received a corticosteroid, as a control group. Patients completed patient-reported outcome assessments at baseline and at 1, 3, 6 and 12 months after injection. The primary outcome was improvement in the VAS score for pain. Secondary outcomes included changes in ASES score, SANE score and the Pittsburgh Sleep Quality Index (PSQI). Treatment failure was defined as persistent pain at 3 months which required a subsequent injection. ResultsThe mean age was 27.7 (±7.4). All the patients completed 12 months clinical follow-up. At 12 months, patients in the PRP group showed a significantly greater improvement in the VAS than patients in the CS group 1.68(0.6) vs 2.3(1.0) (p<0.001). As well, at 12 months follow-up, the 3 scores evaluated were significantly higher in patients treated with PRP than in patients treated with CS ASES 89.8 (6.3) vs 78.0 (8.6) (p<.001); SANE 89.2 (6.3) vs 80.5 (9.6) (p< .001) and PSQI 2.72 (0.6) vs 4.02 (1.7) (p< .001)The overall failure rate, was significantly higher in the CS group (30%) than in the PRP group (12%) (p<0.01) ConclusionOne subacromial PRP injection in patients with rotator cuff tendinopathy showed significantly superior and sustained pain-relieving and functional improvements compared with one corticosteroid subacromial injection assessed by 4 patient-reported outcome scales at 12 months of follow-up. Moreover, the overall failure rate, was significantly higher in the CS group than in the PRP group.