A course of prp therapy, or platelet-rich plasma therapy, for cartilage or meniscus injuries of the knee generally takes three sessions, but there are individual differences in results. Platelet-rich plasma treatment for knee diseases refers to centrifuged platelet-rich plasma that is injected into the knee joint to repair knee diseases, such as meniscus injuries and cartilage injuries of the knee joint. It mainly utilizes the mechanism of action that platelet-rich plasma can mediate chondrocytes for repair, and its long-term clinical effect is to be accumulated by evidence-based medicine. In general, three injections of platelet-rich plasma preparations are usually taken as a course of treatment, such as three injections to promote the repair of cartilage damage in the knee joint, to a certain extent, pain relief and cartilage repair can be achieved. However, for knee joint diseases such as cartilage degeneration, there are great individual differences in treatment effects. Platelet-rich plasma treatment for knee joint diseases should be carried out in a qualified and formal medical institution under the guidance of a doctor who has assessed the condition.