Intra-articular platelet-rich plasma injections versus intra-articular corticosteroid injections for symptomatic management of knee osteoarthritis: systematic review and meta-analysis

BACKGROUND: Intra-articular (IA) corticosteroid (CS) injections are the mainstay of treatment for symptomatic management in knee osteoarthritis (OA), particularly in the UK. IA platelet-rich plasma (PRP) injections are a promising alternative, but no systematic reviews to date have compared them to the current standard of care, IA CS injections. We aim to investigate the effect of IA PRP injections versus IA corticosteroid injections for the symptomatic management of knee OA. METHODS: All published trials comparing IA PRP and CS injections for knee OA were included. MEDLINE, EMBASE, Scopus and Web of Science were searched through June 2020. Risk of bias was assessed using the Cochrane Risk of Bias tool. A random effects model was used to calculate standardized mean difference with 95% confidence interval in WOMAC/VAS score (or subscores), comparing IA PRP to CS injections across studies. RESULTS: Included were eight studies and 648 patients, 443 (68%) were female, mean age 59 years, with a mean BMI of 28.4. Overall, the studies were considered at low risk of bias. Compared with CS injections, PRP was significantly better in reducing OA symptoms (pain, stiffness, functionality) at 3, 6 and 9 months post-intervention (P < 0.01). The greatest effect was observed at 6 and 9 months (− 0.78 (− 1.34 to − 0.23) standard mean deviations (SMD) and − 1.63 (− 2.14 to − 1.12) SMD respectively). At 6 months, this equates to an additional reduction of 9.51 in WOMAC or 0.97 on the VAS pain scales. At 6 months PRP allowed greater return to sporting activities than CS, measured by the KOOS subscale for sporting activity, of magnitude 9.7 (− 0.45 to 19.85) (P = 0.06). Triple injections of PRP, generally separated by a week, were superior to single injections over 12 months follow-up (P < 0.01). CONCLUSIONS: IA-PRP injections produce superior outcomes when compared with CS injections for symptomatic management of knee OA, including improved pain management, less joint stiffness and better participation in exercise/sporting activity at 12 months follow-up. Giving three IA-PRP, with injections separated by a week, appears more effective than 1 IA-PRP injection. PROSPERO TRIAL REGISTRATION NUMBER: CRD42020181928. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12891-021-04308-3.