The Efficacy of Platelet-Rich Plasma on Improving Pain and Function for Lateral Epicondylitis: A Systematic Review and Meta-analysis with Risk-of-Bias Assessment.

PURPOSE To assess the efficacy of PRP for lateral epicondylitis and evaluate its impact on pain and functional outcomes. METHODS This study followed Preferred Reporting Items and Systematic Reviews and Meta-Analyses guidelines. A comprehensive literature search was conducted in September 2019 and repeated in April 2020 using electronic databases PubMed, MEDLINE, and the Cochrane Library. Baseline, 3-month, 6-month, and 12-month data were extracted for visual analog scale (VAS), disabilities of the arm, shoulder and hand (DASH), and modified Mayo Clinic performance index for the elbow (MAYO) scores. Only level 1 studies with patients who had not undergone surgery were included. Outcomes data, study design, demographic variables, PRP formulation, and comparator treatments were recorded. Statistical analyses of pooled weighted mean differences (WMD) were performed and compared to estimated minimal clinically important difference (MCID) values. The Coleman Methodology Score (CMS) was used to assess methodological quality and the Cochrane risk-of-bias assessment was performed. RESULTS This review included sixteen level I studies, 9 (581 total patients, 281 receiving single injections of PRP) of which were quantitatively analyzed. Average age was 41.5 years, 56.8% of patients were female, and mean follow-up was 7.5 months. The mean CMS was 78.94 ± 12.74 (range 59-97) and 5 of 16 studies were at a low risk for bias. Patients who received PRP reported significantly improved VAS scores at 3 months (WMD: -0.85; 95% CI: -1.03, -0.66; p<0.01) and 6 months (WMD: -0.74; 95% CI: -0.98, -0.50; p<0.01) compared to those who received autologous whole blood, though MAYO scores were statistically equivalent. Comparing PRP to corticosteroids, VAS and DASH scores were not significantly different at 3 months, though PRP was superior at 6 months for VAS (WMD: -1.70; 95% CI: -2.65, -0.75; p<0.01) and DASH (WMD: -6.23; 95% CI: -10.78, -1.69; p<0.01). Most differences in VAS and DASH scores exceeded the 5% absolute difference estimate for their respective MCIDs but fell short of the 10% estimate. CONCLUSION Considering the small number of comparable studies, lack of quantification of specific PRP content, considerable heterogeneity between each RCT, and that most effect sizes were equivocal within the framework of two estimated MCID values, the authors can neither scientifically support nor discourage the usage of PRP for lateral epicondylitis despite finding statistically significant improvements in pain and functional outcomes. LEVEL OF EVIDENCE Level I Prognostic.