RESUMEN
BACKGROUND: Supraspinatus tendinopathy is a significant cause of pain and function loss. It has been suggested that platelet-rich plasma (PRP) and prolotherapy are effective treatments for this condition. This study was done to assess and compare the effects of PRP and prolotherapy on shoulder function and pain. The secondary aim was to evaluate the effect of the treatment on shoulder range of motion, supraspinatus tendon thickness, patient satisfaction, and adverse effects. METHODS: This was a randomized, double-blind clinical trial. The study included 64 patients over the age of 18 who had supraspinatus tendinopathy and had not responded to at least three months of conventional treatment. Patients were assigned to either receive 2 mL of PRP (N.=32) or prolotherapy (N.=32). The Shoulder Pain and Disability Index (SPADI) and the Numerical Rating Scale (NRS) were the primary outcomes. Secondary outcomes included shoulder range of motion (ROM), supraspinatus tendon thickness, and adverse effects, which were measured at baseline, 3, 6, and 6 months after injection. At six months, patient satisfaction was assessed. RESULTS: Repeated measures ANOVA showed there was a statistically significant effect of time on total SPADI scores (F [2.75, 151.11], = 2.85, P=0.040) and the NRS (F [2.69, 147.86], = 4.32, P=0.008) within each group. There were no other significant changes over time or between groups. Significantly more patients in the PRP group experienced increased pain lasting less than two weeks after injection (χ2=11.94, P=0.030). CONCLUSIONS: PRP and prolotherapy resulted in improved shoulder function and pain for patients with chronic supraspinatus tendinopathy who did not response to conventional treatment.