BACKGROUND: Platelet-rich plasma (PRP) usage in orthopedics continues to rise, despite guidelines suggesting non-superiority to comparative cohorts. Therefore, we performed a systematic review and meta-analysis on PRP efficacy using two clinical assessments: (1) Visual Analog Scale and (2) Western Ontario and McMaster Universities Osteoarthritis Index. We assessed consistency and clinical relevancy by determining study heterogeneity (eg, sample sizes, ages, body mass index, arthritic severities, etc.). Comparative cohorts were: (A) hyaluronic acid (HA); (B) corticosteroid (CS); (C) normal saline (NS); and (D) exercise therapy. We performed sub-analyses of structural changes assessed on ultrasound, radiograph, or magnetic resonance imaging .
METHODS: We utilized PubMed, Cochrane Library, and Embase databases up to December 1, 2021, according to Preferred Reporting Items for Systematic-Reviews and Meta-Analyses guidelines. Twenty-four studies met criteria, with comparisons to: HA (n = 11); CS (n = 6); NS (n = 5); and exercise therapy (n = 3). Seven studies assessed structural changes. Evaluations utilized a methodological scoring system. I2 statistics and forest plots pooled analyses and delineated study results.
RESULTS: PRP led to Visual Analog Scale and Western Ontario and McMaster Universities Osteoarthritis Index improvements in most studies when compared to HA, CS, and NS (P = .05). Comparison to exercise therapy resulted in inconclusive findings (P = .05). However, substantial heterogeneity (I2 = 76%) was reported due to study variability. No differences were found when assessing structural changes or cartilage thickness by magnetic resonance imaging (standardized mean difference -0.01 [-0.19, 0.18], P = .91).
CONCLUSIONS: PRP may be associated with pain and functional improvements but was not clinically relevant (inconsistent study- and patient-metrics). In addition, PRP did not confer superiority when assessing knee-related structural changes.
Systematic review of PRP injections showing no conclusive benefit compared with standard treatment in OA knee either symptomatically or structurally.
"However, substantial heterogeneity (I2 = 76%) was reported due to study variability". This is why meta-analyses of PRP are sub-par. We see this again and again with PRP. Inconsistencies in, inconsistencies out. I would much prefer to see well done RCTs (over meta-analyses) that actually report things like platelet counts, leukocyte counts, total dose platelets, spin g force and time etc. This is so rare to see in a study. We would never accept such variability in drug studies . Why do we accept them in PRP studies?