PURPOSE: To evaluate the efficacy of platelet-rich plasma (PRP) combined with hyaluronic acid (HA) injections versus HA injections alone for the management of knee osteoarthritis (OA).
METHODS: This study was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Eligible randomized-controlled trials and observational studies directly comparing combined PRP-HA injections with HA injections alone were identified through a search of PubMed, Scopus, and Cochrane Central databases from inception to May 2020. A random effects model meta-analysis was conducted and the I statistic was used to assess for heterogeneity.
RESULTS: Four studies comprising 377 patients (PRP-HA: 193, HA: 184) with knee OA ranging from I-IV Kellgren-Lawrence grading scale were included. The final follow-up was 12 months in 3 studies and 6 months in 1 study. Patients who received PRP combined with HA had significantly greater improvements compared with those injected with HA alone in terms of visual analog scale scores at 3-month (standardized mean difference [SMD] 1.13; 95% confidence interval [CI] 0.56-1.70; I = 56.7%; P < .001), 6-month (SMD 1.08; 95% CI 0.54-1.62; I = 67.9%; P < .001), and 12-month (SMD 1.13; 95% CI 0.74-1.52; I = 0.0%; P < .001) and 12-month Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical functioning (SMD 0.91; 95% CI 0.65-1.17; I = 0.0%; P < .001) and 12-month WOMAC stiffness (SMD 1.09; 95% CI 0.80-1.38; I = 0.0%; P < .001) scores. No difference was identified in terms of 12-month WOMAC pain score (SMD 0.36; 95% CI -0.19 to 0.91; I = 74.1%; P = .195).
CONCLUSIONS: Symptomatic patients with knee OA who were injected with a combination of PRP and HA demonstrated greater improvement in pain and function compared with patients who received HA injections only, as assessed by 3-, 6-, and 12-month visual analog scale scores and 12-month WOMAC physical function and stiffness scores. This study provides encouraging evidence for the use of the combined PRP-HA injections in the management of symptomatic patients with knee OA.
LEVEL OF EVIDENCE: III (meta-analysis of randomized and non-randomized comparative trials).