Treatment of Knee Osteoarthritis by Intra-articular Injection of Bone Marrow Mesenchymal Stem Cells

Purpose: To determine the safety, feasibility and effectiveness (clinical and radiological) of intra-articular administration of autologous mesenchymal stem cells (MSCs) in patients with knee osteoarthritis. Patients and methods Clinical trial phase I- II, randomized , multicenter , with three treatment arms and 10 patients for each group. The investigators compare the intraarticular injection of hialuronic acid against the administration of two different doses of mesenchymal stem cells with hialuronic acid according to the following scheme: 1. Group A: intra-articular injection of hyaluronic acid (Hyalone®). Single dose. 2. Group B: Low Dosage of MSCs . Intra-articular injection of 10 million autologous mesenchymal progenitor stem cells cultured ex - vivo (cell suspension sterile small volume (5-10 ml ) in a vehicle suitable for intraarticular injection ) followed by an intraarticular injection Hiaurónico Acid ( Hyalone®). 3. Group C : High dose of MSCs. Intra-articular injection of 100 million autologous mesenchymal progenitor stem cells cultured ex - vivo ( cell suspension sterile small volume (5-10 ml ) in a vehicle suitable for intraarticular injection ) followed by an intraarticular injection Hiaurónico Acid (Hyalone®). The primary endpoint is safety and feasibility. The investigators registered the occurrence of complications and / or adverse effects during the study. In addition the investigators assess the response to intra-articular infusion of CMM analyzing the following parameters: * Clinical assessment of pain and function (Baseline, 1, 3, 6 and 12 months since treatment): VAS , WOMAC , KOOS , EuroQol, SF-16, Lequesne , WOMAC , KOOS. * Radiographic (baseline, 6 and 12 months since treatment): Femorotibial space. * Radiographic using MRI (baseline, 6 and 12 months since treatment): by assessing the number location of the lesions , cartilage thickness , signal intensity , subchondral bone alteration , volume and WORMS and dGEMRIC protocols.