The purpose of this study was to perform a systematic review and meta-analysis comparing intra-articular knee injection of PRP and hyaluronic acid and investigate clinical outcomes and pain at both 6 and 12 months.
A systematic review of Medline, Embase, Scopus, and Google Scholar was performed in the English and German literature reporting on intra-articular knee injections for knee osteoarthritis. All level 1 and 2 studies with a minimum of 6-month follow-up in patients with knee osteoarthritis from 2010 to 2019 were included. Clinical outcome was assessed by WOMAC and IKDC scores and pain by VAS and WOMAC pain scores. Subgroup analysis for autologous platelet-rich plasma (ACP) was performed. Publication bias and risk of bias were assessed using the Cochrane Collaboration’s tools. The GRADE system was used to assess the quality of the body of evidence. Heterogeneity was assessed using χ and I statistics.
Twelve studies (1,248 cases; 636 PRP, 612 HA) met the eligibility criteria. The pooled estimate demonstrated non-significant differences between PRP and HA for clinical outcomes at 6 months (p = 0.069) and at 12 months (p = 0.188). However, the pooled estimate for pain did demonstrate significant differences in favour of PRP at 6 months (p = 0.001) and 12 months (p = 0.001). For the ACP subgroup (249 cases), the pooled estimate for these studies demonstrated significant differences in favour of PRP (p < 0.0001) at 6 months.
The results of this systematic review and meta-analysis suggest that PRP is superior to HA for symptomatic knee pain at 6 and 12 months. ACP appears to be clearly superior over HA for pain at both 6 and 12 months. There were no advantages of PRP over HA for clinical outcomes at both 6 and 12 months.
Level 2; systematic review and meta-analysis.