I congratulate the International Olympic Committee consensus panel1 on having produced as clear a summary of the current understanding of the basic and clinical science relating to platelet-rich plasma (PRP) as the body of published literature allows. While there was initially great hope in sports medicine circles that PRP would become the magic bullet for injuries, recent trials such as that of de Vos et al2 have failed to provide the conclusive evidence so desired.

This is not surprising. The more we learn about tissue regeneration, the more apparent it becomes how complex a process it is. Tissue regeneration is not a passive phenomenon, instead it is a highly coordinated interplay of multiple cell lines at different stages of maturation. Different cellular and humoral components play their different roles.

The process can be likened to the repair of a collapsed building. Consider muscle injury. The initial cells on the scene, due to bleeding, are platelets, but they appear to …