Since this is a developing field of medicine, new studies are being performed and evidence for the effectiveness of stem cell and platelet-rich plasma (PRP) treatments is constantly growing. In a recent study, more than 91% of the 1,100 patients who received adult stem cell treatment for knee osteoarthritis had a 50% improvement in their pain and function one year after their treatment. In addition, patients can have improved results from receiving these types of biologic treatments, when in the past they have not responded to the more traditional procedures and therapies.