A standardised PRP pathway beat ad hoc PRP for early knee osteoarthritis, but had no placebo arm

Design

Multicentre, double-blind randomised controlled trial

Population

240 patients with Kellgren-Lawrence grade I–II knee osteoarthritis at three Chinese hospitals

Primary outcome

VAS pain, WOMAC and IKDC at 12 months

Effect

VAS −2.98 (95% CI −3.64 to −2.32); WOMAC −8.63 (−11.35 to −5.90), pathway vs conventional

This three-centre, double-blind trial in China randomised 240 patients with Kellgren-Lawrence grade I or II knee osteoarthritis to a standardised PRP clinical pathway or to physician-directed conventional PRP care. The pathway bundled patient selection criteria, quality-controlled leukocyte-poor PRP, ultrasound-guided injection, staged rehabilitation and scheduled follow-up.

At 12 months the pathway produced larger improvements in VAS pain (mean difference −2.98, 95% CI −3.64 to −2.32), WOMAC total (−8.63, −11.35 to −5.90) and IKDC (10.25, 8.37 to 12.13). More patients reached a minimal clinically important difference, satisfaction was higher, and adverse events were fewer (14.8% vs 31.9%). Costs were similar.

The result says more about how PRP is delivered than about whether it works. There was no saline or placebo arm, and the components were bundled, so the trial cannot say whether the gain came from the PRP preparation, the image guidance, the rehabilitation or the follow-up. PRP for knee osteoarthritis remains contested and is not uniformly recommended in guidelines. Where clinics in India already offer it, this supports doing it in a standardised, guided and rehabilitated way rather than as a one-off injection.

• If you offer PRP for early knee osteoarthritis, use a defined protocol: leukocyte-poor preparation, image guidance and a structured exercise programme.
• Limit PRP to patients with mild radiographic disease, as in this trial (Kellgren-Lawrence I–II).
• Pair any injection with supervised rehabilitation, which may account for part of the benefit.
• Tell patients that evidence for PRP itself against placebo remains mixed.

Why it matters

Much of the inconsistency in PRP trials may come from how it is delivered rather than the preparation itself.

Don't overread it

Without a placebo group, this trial does not show that PRP works for knee osteoarthritis.

The statistics, in plain English

The pain difference of about 3 points on a 10-point scale is large, and the narrow intervals show it is unlikely to be chance. But because both arms received PRP and the pathway changed several things at once, the comparison measures the package, not the plasma.

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