Injury of the knee joint can lead to a range of adverse outcomes and significantly contributes to the development of the knee osteoarthritis. Currently, autologous platelet-rich plasma is used as a promising and safe method of treating osteoarthritis. Such plasma contains various growth factors, some of which are secreted after platelet activation. These factors can trigger a regenerative response and improve the metabolic functions of damaged structures. However, there are different protocols for preparing platelet-rich plasma, which results in preparations with different amounts of bioactive substances. As a result, the data obtained on the effect of platelet-rich plasma on the restoration of hyaline cartilage of the knee joint are very contradictory. A search for publications on a given topic was performed in the eLibrary, PubMed (MEDLINE), Ovid, Science Direct, Google Scholar databases, and also a search was conducted for clinical trial data on the treatment of knee osteoarthritis with platelet-rich plasma over the past 20 years. Publications dealing with other aspects of the application of this technology were excluded from the search results. An analysis of published clinical trial results found that, in most cases, patients treated with platelet-rich plasma reported improved pain and joint function, with only three studies showing no difference between platelet-rich plasma and placebo. Thus, this technology is generally promising for use in the treatment of knee osteoarthritis, however, methods of obtaining and activating platelet-rich plasma, as well as the age and comorbidities of the patient, may affect the effectiveness of therapy.