Recently an articular cartilage repair has been given much attention in the orthopaedic field. Cartilage regeneration capacity is very limited. Optimal approach seems to be a delivery of natural growth factors. Autologous platelet-rich plasma (PRP) contains proliferative and chemoattractant growth factors. The objective of the present study was to determine if PRP can increase tibiofemoral cartilage regeneration and improve knee function.