Platelet-Rich plasma vs corticosteroid for primary frozen shoulder: Meta-analysis of randomized trials

BackgroundExisting evidence comparing the effectiveness of platelet-rich plasma (PRP) and corticosteroid (CS) injections for primary frozen shoulder (FS) has yielded inconsistent results.ObjectivesThis study aimed to compare PRP and CS injections for primary FS.MethodsThis systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was registered in International Prospective Register of Systematic Reviews (PROSPERO) with the registration ID CRD42024543342. We searched PubMed, EMBASE, The Cochrane Library, and Web of Science for randomized controlled trials (RCTs) comparing PRP and CS injections in patients with primary FS. Data on change (Δ, defined as endpoint value minus the baseline value) of pain (Visual Analogue Scale [VAS] scores), range of motion (ROM), functional scores (Disabilities of the Arm, Shoulder and Hand [DASH], Shoulder Pain and Disability Index [SPADI], University of California at Los Angeles shoulder scale [UCLA]), and complications were extracted and analyzed. Risk of bias was assessed using the Cochrane Risk of Bias 2 (RoB 2) tool, and the evidence quality was evaluated with Grading of Recommendations, Assessment, Development and Evaluation (GRADE). Statistical evaluations were performed using Review Manager V.5.4.1.ResultsA total of 7 RCTs involving 692 participants were included, with overall low risk of bias per RoB 2. Heterogeneity was low to moderate (I²=0-59%) across outcomes. PRP and CS injections showed comparable short-term (up to 1 month) improvements in pain and functional scores (all P ＞ 0.05, I²=0-48%). At 3 and 6 months, PRP statistically outperformed CS in pain (Δ VAS: WMD -0.62 at 3 months, -1.06 at 6 months), ROM (Δ abduction: +16.68°, Δ external rotation: +12.22°, Δ internal rotation: +8.35° at 3 months), and function (Δ SPADI: -11.52 at 3 months, -17.23 at 6 months; Δ DASH: -8.46 at 6 months; Δ UCLA: +4.35 at 3 months), all P < 0.001, I²=0-59%. Complications were rare and similar (0.86% PRP vs. 0.87% CS; OR 0.98, P = 0.98, I²=0%). The quality of evidence was low to moderate across outcomes.ConclusionsBased on low to moderate evidence quality, both treatments showed comparable short-term improvements in pain and function (up to 1 month), with similarly low rates of mild complications. However, PRP injections demonstrated statistically significant improvements in pain, function, and ROM at 3- and 6-month follow-ups. Improvements at 6 months are highly likely to be clinically significant over CS, with lower likelihood at 3 months. These findings should be interpreted cautiously.