Clinical Effects of Additional Platelet-Rich Plasma Application to Exercise Therapy in Patients with Subacromial Impingement Syndrome: A Double-Blind Randomized Controlled Trial.

Background: Exercise therapy (ET) is the main and initial treatment modality for treating subacromial impingement syndrome (SIS). The isolated or combined use of platelet-rich plasma (PRP) applications in treating SIS is increasing and promising. A comparison was made on the effectiveness of ET alone and in combination with PRP on pain, functionality, and quality of life (QoL) in patients with SIS. Purposes/Hypothesis: The purposes of this study were to (1) investigate the possible positive effects of PRP injections combined with ET in treating SIS on pain, functionality, and QoL and (2) propose an alternative treatment protocol. It was hypothesized that the group receiving PRP applications in addition to ET would have a better QoL due to less pain and higher functionality 6 months after treatment. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: Volunteer patients diagnosed with SIS were included based on history and physical examination findings. All participants underwent magnetic resonance imaging to confirm the diagnosis and exclude possible accompanying pathologies. The patients were randomly divided into 2 groups. The first group underwent ET at home for 8 weeks (ET group), and the second group received the same ET program and an additional 2 PRP injections, at the beginning of the study and the end of the fourth week (PRP group). Patients were evaluated initially and 6 months after the treatment using the visual analog scale (VAS) for pain score, Constant-Murley Score (CMS), and the 36-Item Short Form Health Survey (SF-36). The Kolmogorov-Smirnov test determined the conformity of the data to a normal distribution, chi-square analysis was used to compare categorical variables between groups, and the Mann-Whitney Results: A total of 67 patients were initially enrolled; 5 were excluded and 6 were lost to follow-up (1 because of a COVID diagnosis). Thus, 56 patients (56 shoulders) were included for analysis. There were 28 patients in the ET group and 28 patients in the PRP group. There were no statistical differences between groups regarding participant characteristics and clinical evaluations before treatment. A statistically significant improvement was observed in pain (VAS subgroups), functionality (CMS subgroups), and QoL (SF-36 subgroups) evaluations of patients in both the ET and the PRP groups compared with before the treatment and 6 months after treatment ( Conclusion: Our study showed that both isolated ET and additional PRP application to ET are effective methods in SIS treatment regarding pain, function, and QoL. Combining ET with PRP was superior in reducing pain and improving abduction degree and strength.