Design: Systematic review and meta-analysis of randomised trials
Population: 12 trials, 1,200 patients with knee osteoarthritis
Primary outcome: Imaging-based structural outcomes
Effect: No difference in medial tibial cartilage or defect progression; patellofemoral cartilage SMD 0.94 (95% CI 0.53 to 1.34)

A meta-analysis of 12 randomised trials in 1,200 patients assessed whether platelet-rich plasma (PRP) injections change knee osteoarthritis on imaging.

PRP was associated with more patellofemoral cartilage thickness or volume (standardised mean difference 0.94) and less bone marrow oedema (-0.40). But there was no difference in medial tibial cartilage, cartilage defect progression, osteophytes, cysts or overall synovitis.

The authors conclude that PRP has not been shown to modify disease structure. The two positive findings are isolated among many null ones and could reflect chance or measurement differences.

PRP is widely marketed in India and elsewhere as regenerative. This review gives a clear basis for telling patients that any benefit is on symptoms, not on rebuilding the joint.

Do not describe PRP as cartilage-regenerating or disease-modifying.
If PRP is discussed, frame any benefit as possible symptom relief only.
Medial compartment cartilage, the usual site of disease, showed no change.
Keep exercise and weight management as first-line treatment.

Why it matters

It removes the strongest marketing claim made for PRP.

The statistics, in plain English

When many outcomes are tested, one or two will often look significant by chance. Here most structural measures showed no difference, which is the more reliable signal.