Platelet Concentration Is Not Associated With Improved Pain for Partial-Thickness Rotator Cuff Tears Treated With Platelet-Rich Plasma: A Systematic Review and Meta-analysis With Meta-regression of Level 1 Randomized Controlled Trials.

BACKGROUND: Platelet-rich plasma (PRP) has emerged as a nonoperative treatment option to manage pain and improve functionality in patients with partial-thickness rotator cuff tears. Previous studies examining the efficacy of PRP for the management of partial-thickness rotator cuff tears describe heterogeneous results. PURPOSE: To determine whether platelet concentration of a PRP injection as management for partial-thickness rotator cuff tears affects visual analog scale (VAS) pain scores. STUDY DESIGN: Systematic review; Level of evidence, 1. METHODS: A systematic review was performed by searching PubMed, the Cochrane Library, and Embase to identify level 1 randomized controlled trials (RCTs) that evaluated the clinical efficacy of PRP for the management of partial-thickness rotator cuff tears. The search phrase used was "rotator cuff partial platelet rich plasma." Included RCTs were classified as utilizing high-dose or low-dose PRP based on their platelet concentration factor as greater than a 4-fold increase over whole blood. The primary outcome evaluated was the standardized mean differences of VAS scores. Mixed-effects and random effects meta-analyses were performed along with meta-regression to evaluate relationships in VAS scores associated with PRP platelet dose. RESULTS: Ten studies met inclusion and exclusion criteria, including a total of 635 patients (PRP, n = 307; control, n = 328). The mean patient age at the time of injection was 50.6 years, the mean follow-up time was 10.0 months, and the mean male sex distribution was 44.4%. Of the 10 studies, 6 studies utilized high-dose PRP and 4 studies utilized low-dose PRP. In both the meta-analysis and the meta-regression analyses, there were no significant differences in mean postinjection VAS scores between platelet dosage groups (P = .36 and P = .37, respectively). CONCLUSION: Among level 1 RCTs reporting VAS pain scores after PRP injection for partial-thickness rotator cuff tears, platelet concentration was not significantly associated with improved pain outcomes. However, substantial heterogeneity and inconsistent reporting of PRP composition limit the certainty of this finding.