Background. Knee osteoarthritis (OA) is an age-related progressive condition that has resulted in a significant burden worldwide. In this survey, we aimed to compare intra-articular hypertonic saline (HS) and hyaluronic acid (HA) safety and efficacy in the pain and function improvement of patients suffering from knee OA. Eventually, we made a comparison with physical therapy (PH), in a six-month follow-up. Methods. This study is a three-arm single-blinded randomized clinical trial evaluating 130 radiographically confirmed knee osteoarthritis patients suffering from chronic knee pain. A group of participants received three weekly injections of HA (Hyalgan ® ), while the other group experienced an injection of five milliliters of 5% HS and the third group engaged in ten-session physiotherapy. Patients assessed before intervention, one, three, and six months post-intervention using the visual analogue scale (VAS) for pain and Knee injury and osteoarthritis outcome score (KOOS) for function and quality of life (QOL). Results. In this study, We did not identify any remarkable adverse effects. All KOOS subscales scores decreased in the HA and HS group significantly. A similar trend was detected in pain improvement, considering VAS. PH group experienced only pain reduction but not function improvement. Comparing two injected agents, HS group obtained better scores not only in pain and symptom reduction, but also in function and QOL improvement. Conclusions. However, both HS and HA can be effectively used for improving function and reducing pain and unpleasant symptoms in knee OA patients, HS prolotherapy demonstrated more acceptable outcomes through six-month follow-up.