Platelet-Rich Plasma Injections Are Inferior to Corticosteroid Injections for Short-Term Pain Relief: A Prospective, Double-Blinded, Randomized Controlled Trial.

BACKGROUND

We aimed to evaluate and compare the clinical benefits of platelet-rich plasma (PRP) injections compared to corticosteroid (CS) injections in patients who have mild to moderate symptomatic knee osteoarthritis in a double-blinded randomized control trial. We aimed to compare improvements in the following outcomes at six weeks and three months: 1) pain scores, including Visual Analog Scale (VAS) and Numeric Pain Rating Scale (NPRS); and 2) functional scores, including Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Knee Injury and Osteoarthritis Outcome Score (KOOS).

METHODS

In this double-blinded randomized control trial, 52 patients who had symptomatic, radiographically confirmed knee osteoarthritis were enrolled. A power analysis determined that a sample size of 52 was required. Patients were randomized to receive treatment with an intra-articular injection of CS (n = 26) or PRP (n = 26). We evaluated clinical outcomes, including VAS, NPRS, WOMAC, and KOOS scores at baseline, six weeks, and three months after injection. We also determined if our clinical outcomes met the minimal clinically important difference (MCID) based on the following scores reported in the literature: 19.9 for VAS and 2 for NPRS.

RESULTS

There was no difference in baseline VAS, NPRS, KOOS, or WOMAC scores between the CS and PRP cohorts. At six weeks, CS patients had significantly greater reductions from baseline in VAS (-24.26 versus -7.38, P = 0.033) and NPRS (-2.24 versus -0.92, P = 0.042). The MCID for both VAS and NPRS was met in the CS cohort at 6 weeks, but not in the PRP cohort. At three months, CS and PRP patients experienced similar improvements in VAS (-18.27 versus 13.27, P = 0.610) and NPRS (-1.81 versus -0.65, P = 0.798), respectively. Neither cohort met the MCID at three months. Both groups experienced similar improvements in KOOS and WOMAC.

CONCLUSIONS

When comparing PRP to CS injections in patients who have mild to moderate knee osteoarthritis, CS demonstrated greater pain reduction at six weeks. Based on these findings, expectations regarding the clinical utility of PRP should be tempered.