Platelet-rich plasma injections for knee osteoarthritis provide no improvement in pain relief or reduction in disease progression compared with placebo, an Australian study shows.

The findings add to growing evidence against the use of autologous blood products to treat musculoskeletal conditions, the researchers say.

Intra-articular injections of platelet-rich plasma (PRP) can cost up to $500 per shot and have been touted as an alternative to pharmacological and surgical interventions for joint pain.

But lead researcher Professor Kim Bennell, from the University of Melbourne, said there was a dearth of high-quality evidence to back this indication.