Autologous platelet-rich plasma versus hyaluronic acid, corticosteroids or saline for knee osteoarthritis: can blood draw volume serve as a proxy for platelet dose? A systematic review and meta-analysis.

PURPOSE: To compare platelet-rich plasma (PRP) with hyaluronic acid (HA), corticosteroid (CS), or saline placebo (NS) for symptomatic knee osteoarthritis (OA) and to assess whether total blood-draw volume, a proxy for platelet dose, is associated with treatment effect.

METHODS

Following PRISMA, randomized controlled trials comparing intra-articular PRP with HA, CS, or NS were identified. Random-effects meta-analyses estimated mean differences (MDs) in pain (VAS) and function (WOMAC) at six and twelve months. Risk of bias was assessed with RoB 2.0 and certainty of evidence with GRADE. Subgroup analyses stratified PRP vs HA trials by total blood draw volume (< 40 mL vs ≥ 40 mL).

RESULTS

Sixty-two trials (n = 4,969) were included. PRP improved VAS and WOMAC versus HA, CS, and NS at six months and remained superior versus HA and CS at twelve months (insufficient studies for twelve-month PRP vs NS). In PRP vs HA trials, blood draw volume ≥ 40 mL was associated with larger improvements in six-month WOMAC (P = 0.004) and twelve-month VAS (P = 0.029). Heterogeneity was substantial (I2 > 90% for most analyses), and evidence certainty ranged from moderate to very low.

CONCLUSION

PRP provides superior patient-reported pain and function outcomes compared with HA, CS, and NS through six months, with benefits maintained to twelve months versus HA and CS in longer-term trials. Blood-draw volume may be a useful alternate when platelet dose is unreported.