To compare the effectiveness of intra-bursal injection of single-dose platelet-rich plasma (PRP) against corticosteroids under ultrasonography guidance in shoulder impingement syndrome (SIS).

This single-blind randomized controlled trial was conducted on 60 participants with a clinical diagnosis of SIS from a selected orthopedic clinic. Thirty participants in each arm were given a single dose of either PRP or triamcinolone acetonide into the subacromial sub-deltoid bursa (SASD) under ultrasonography guidance. The outcome variables assessed were the severity score of pain and the degree of shoulder abduction. Post-treatment follow-up was done in 1 week, 3 months, 6 months, and 1 year.

At 1 week, the triamcinolone arm showed a statistically significant reduction of pain (p = 0.039) when compared to PRP. In the long term, PRP showed statistically significant improvement in shoulder abduction, compared to the triamcinolone injection (p = 0.012).

PRP and triamcinolone in the SASD bursa could be considered as safe treatment options for SIS under ultrasonography guidance. While triamcinolone was effective in short-term pain reduction, PRP was effective in long-term improvement in shoulder abduction.