Tehran University of Medical Sciences Journal of Orthopedic and Spine Trauma 2538-2330 5 1 2020 07 20 21 24 Behrouz Tavana AJA UnivAssistant Professor, Department of Physical Medicine and Rehabilitation, School of Medicine, AJA University of Medical Sciences, Tehran, Iranersity of Medical Sciences Sirous Azizi Assistant Professor, Department of Physical Medicine and Rehabilitation, School of Medicine, AJA University of Medical Sciences, Tehran, Iran Sharif Najafi Assistant Professor, Department of Physical Medicine and Rehabilitation, School of Medicine, AJA University of Medical Sciences, Tehran, Iran Ensie Taftian Clinical Resident, Department of Physical Medicine and Rehabilitation, School of Medicine, AJA University of Medical Sciences, Tehran, Iran Nastaran Maghbouli Clinical Resident, Department of Physical Medicine and Rehabilitation, Imam Khomeini Hospital Complex, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran 2020 02 25 2020 03 21 Background: To report the effectiveness of intra-articular injection of hypertonic saline in pain reduction and function improvement of patients with knee osteoarthritis. Methods: Patients with knee pain and dysfunction who fulfilled the American College of Rheumatology criteria and whose illness was sub-acute or chronic were enrolled. We performed a single Intra-articular injection of 5cc of hypertonic saline solution 5%. Measured outcomes were Visual Analogue Scale (VAS) score and Knee injury and osteoarthritis outcome score (KOOS) evaluated before and 1 month after intervention. Results: a total of 28 patients with mean age of 66.3 years were surveyed. Overall, study participants reported clinically and statistically significant reduction in  VAS and KOOS subscales for symptoms, pain, function, daily living, sports, recreational activities and quality of life in one month of follow-up with respect to the patients’ mean baseline scores which were reduced by 24.47%, 42.74%, 54.96%, 43.78% and 63.63%, respectively (P-value<0.05 for all comparisons). Although obese patients (BMI≥30 kg/m2) showed less improvement in terms of pain, sports and quality of life subscales of KOOS subscales, compared with non-obese patients (BMI<30 kg/m2), VAS scale difference was not significant. Conclusions: Intra-articular injection of hypertonic saline yields a statistically and clinically significant short-term pain reduction and functional improvement of patients with knee osteoarthritis. https://jost.tums.ac.ir/index.php/jost/article/view/161 https://jost.tums.ac.ir/index.php/jost/article/download/161/146