Mesenchymal stem cells are pluripotent cells that can be obtained from various tissues .They have shown capabilities to differentiate into bone,cartilage,muscle,and adipose tissue, representing a new clinical strategy in regenerative medicine.An increasing number of reports have demonstrated effectiveness of percutaneous intra-articular infusion of MSCs in arthritic disease. In this study we perform a single intra articular injection of cultured mesenchymal stem cells in patients suffering from osteoarthritis, with the aim to assess its clinical safety and efficacy.Patients are assessed for response with MRI, X-Ray examination, WOMAC osteoarthritis index,VAS, and SF36 2,4,8 weeks and 6, and 12 months post infusion.