OBJECTIVES: To observe, under actual conditions of use, the pain effect obtained, in the context of management of knee osteoarthritis, using hyaluronic acid (injectable route). METHODS: Pragmatic, longitudinal and prospective follow-up carried out by rheumatologists in the context of their daily professional activities; the investigator does not change the prescription or management habits. RESULTS: A total of 191 patients are treated with hyaluronic acid. The average age is 64.72 years (±7.34). Average pain during activities of daily living (ADL) was measured by means of a visual analogue scale (VAS). It is 50.12±19.32 at inclusion. At 6 months, this same average pain measured under the same conditions is 36.95. At 6 months, this same average pain measured under the same conditions is 36.95±25.10. A third measurement at 12 months situates it at 38.10±23.19. Pain during ADL is significantly reduced between inclusion and month 6 (p=0.0023) and between inclusion and month 12 (p=0.0012). With regard to pain measured at rest, it was also measured at inclusion, at 6 and 12 months, by means of VAS. There is a significant reduction in pain at rest between inclusion and 6 months (p=0.0004) and the reduction between inclusion and month 12 is also significant (p=0.0007). At inclusion, 6 and 12 months, the average pain observed is 33.48±22.45, 19.90±19.88 and 21.64±22.94, respectively. CONCLUSIONS: Our study, which assesses the effect on pain obtained in the context of management of subjects with knee osteoarthritis, using hyaluronic acid, showed a reduction in pain during ADL. This reduction in pain, which is significant at 6 months, then perpetuated at 12 months, shows the relevance of the treatment.