Simental‐Mendía, Mario

Background: Lateral epicondylitis, or tennis elbow, is a painful degenerative disorder that commonly occurs in adults between 40 and 60 years of age. Normal saline (NS) injections have been used as placebo through a large number of randomized controlled trials (RCTs) focused on the treatment of lateral epicondylitis. Purpose: This meta-analysis of RCTs aimed to assess the therapeutic effect of NS injections on lateral epicondylitis symptoms and compare results with established minimal clinically important difference criteria. Study Design: Systematic review and meta-analysis. Methods: MEDLINE, Embase, Web of Science, and Scopus databases were searched for clinical trials reporting pain and joint function with the visual analog scale, Patient-Rated Tennis Elbow Evaluation, and Disabilities of the Arm, Shoulder and Hand in patients with lateral epicondylitis. The meta-analysis was conducted with a random effects model and generic inverse variance method. Heterogeneity was tested with the I 2 statistic index. Results: A total of 15 RCTs included in this meta-analysis revealed a significant improvement in pain (mean difference, 3.61 cm [95% CI, 2.29-4.92 cm]; P < .00001; I 2 = 88%; visual analog scale) and function (mean difference, 25.65 [95% CI, 13.30-37.99]; P < .0001; I 2 = 82%; Patient-Rated Tennis Elbow Evaluation / Disabilities of the Arm, Shoulder and Hand) after NS injection (≥6 months). Conclusion: NS injections yielded a statistically significant and clinically meaningful improvement in pain and functional outcomes in patients with lateral epicondylitis. New research should focus on better methods to diminish the potential confounders that could lead to this effect because NS injections could mask the real effect of an active therapeutic intervention in RCT. Registration: CRD42019127547 (PROSPERO).

Background: Reports have concluded that platelet-rich plasma (PRP) is an effective and safe biological approach in the treatment of knee osteoarthritis (OA). However, no consensus has been established regarding the number of injections required to observe a therapeutic effect. Purpose: To compare the clinical effectiveness reported in randomized controlled trials (RCTs) of single versus multiple PRP injections in the treatment of knee OA. Study Design: Systematic review; Level of evidence, 1. Methods: A comprehensive search was conducted for RCTs published between 1970 and 2019 that compared the effect of single versus multiple PRP injections on pain and functionality in patients with knee OA. Searched databases included MEDLINE, Scopus, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials. A data extraction form was designed to obtain bibliographic information of the study as well as patient, intervention, comparison, and outcomes of interest data. A random-effects model was used to pool quantitative data from the primary outcomes. Results: We included 5 clinical trials with a low-moderate risk of bias that reported data for 301 patients. Meta-analysis showed that, at 6 months after the intervention, single and multiple (double or triple) injections had similar pain improvement, with no significant differences (standardized mean difference [SMD], 0.61 [95% CI, −1.09 to 2.31]; I 2 = 97%; P = .48). A significant improvement in knee functionality was observed in favor of multiple injections (SMD, 2.29 [95% CI, 0.45-4.12]; I 2 = 97%; P = .01). Subanalysis showed that the significant improvement was only evident for the results of single versus triple injections (SMD, 3.12 [95% CI, 0.64-5.60]; I 2 = 97%; P = .01). Conclusion: According to our results, a single injection was as effective as multiple PRP injections in pain improvement; however, multiple injections seemed more effective in joint functionality than a single injection at 6 months. We consider that the available evidence is still insufficient, and future research on this specific topic is needed to confirm our results.