- Design
- Systematic review and meta-analysis of 12 RCTs
- Population
- 1,200 patients with knee osteoarthritis
- Primary outcome
- Imaging-based cartilage and MRI structural scores
- Effect
- Patellofemoral cartilage SMD 0.94 (0.53–1.34); no difference in medial tibial cartilage
This meta-analysis pooled 12 randomised trials with 1,200 patients that measured imaging-based structural outcomes after platelet-rich plasma injection for knee osteoarthritis.
PRP was associated with more patellofemoral cartilage thickness or volume (SMD 0.94, 95% CI 0.53–1.34) and less bone marrow oedema (SMD −0.40). But it did not change medial tibial cartilage, cartilage defect progression, osteophytes, subchondral cysts or synovitis. The authors judge the effects limited and inconsistent.
PRP is widely marketed in India and elsewhere as a way to 'regrow cartilage'. These data do not support that claim. Any role it has rests on symptom relief, which this review did not assess, and patients paying for repeat injections should hear that structural benefit has not been shown.
- Do not present PRP as a cartilage-regenerating or disease-modifying treatment.
- Medial tibial cartilage, the usual site of knee osteoarthritis, showed no structural benefit.
- Isolated patellofemoral and bone marrow oedema signals are not yet reliable.
- If offering PRP, frame any benefit as possible symptom relief and discuss cost of repeat injections.
Why it matters
It removes the structural argument that underpins much PRP marketing for knee osteoarthritis.
Don't overread it
This review looked at imaging only; it does not answer whether PRP relieves pain.
The statistics, in plain English
An SMD of 0.94 for patellofemoral cartilage is large, but when one outcome out of many is positive and the rest are not, chance and measurement differences between trials are plausible explanations.
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