To study the clinical and paraclinical characteristics of primary knee osteoarthritis. To assess the effectiveness and safety of autologous platelet-rich plasma therapy in treament of primary knee osteoarthritis. | We studied 70 patients (106 joints) completed 6-month follow-up period, 30 patients (44 knee) completed 12-month follow-up period. Considering the group completed its own follow-up period: 6 months with PRP group unsatisfied lower than the rate in the HA group, statistically significant with p <; the corresponding figure at 12 months was tracking PRP group was lower than the HA group (Table ). However, we classified the patients (in the joint) track give reason not better or increased pain in patients group (joint) are not satisfied with the treatment results, while the proportion dissatisfied with it PRP therapy is (5 + 2)/(58 + 2), with ; proportion dissatisfied with the HA treatment group (7 + 5)/(48 + 5), by . Such ratios are not satisfied with the results of treatment of low PRP treatment group than in the treatment group had statistically significant HA. At the time the group completed 6 months follow-up after treatment of the percentage of very satisfied group was PRP treatment is higher than of the BP group, p <; after 12 months of follow-up ratio is of the PRP group versus 0% in the HA group with p < (Table ).