Research into the biology of bone, ligament, and tendon healing has led to the development of a variety of products designed to help stimulate biologic factors and promote healing. The use of the autologous and recombinant products is a rapidly growing field of orthopaedics focusing on manipulating growth factors and secretory proteins to maximize the healing of bone and soft tissues. Despite their clinical use, many of these products have not been studied using rigorous scientific standards. Platelet-rich plasma (PRP) is an example of one such autologous product that has been utilized and studied since the 1970s. Platelet-rich plasma has been used clinically in humans for its healing properties attributed to the increased concentrations of autologous growth factors and secretory proteins that may enhance the healing process on a cellular level.