Treatment of Osteoarthritis by Intra-articular Injection of Bone Marrow Mesenchymal Stem Cells With Platelet Rich Plasma

Purpose: To determine the safety, feasibility and effectiveness (clinical and radiological) of intra-articular administration of autologous mesenchymal stem cells (MSCs) with platelet richa plasma (PRGF) in patients with knee osteoarthritis. Patients and methods Clinical trial phase I- II, randomized , multicenter , with two treatment arms and 19 patients for each group. The investigators compare the intraarticular injection of against the administration of two different doses of mesenchymal stem cells with hialuronic acid according to the following scheme: 1. Group A: 3 intra-articular injections of platelet rich plasma (PRGF®) separated by 7 days. 2. Group B: 3 intra-articular injections of platelet richa plasma (PRGF®) separated by 7 days and one with Mesenchimal stems cells. 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 of platelet richa plasma (PRGF®). The treatment is completed with 2 more injection of platelet richa plasma (PRGF®) separeted by one week. 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 and 12 months from treatment): Femorotibial space. * Radiographic using MRI (baseline and 12 months from treatment): by assessing the number location of the lesions , cartilage thickness , signal intensity , subchondral bone alteration , volume and WORMS and dGEMRIC protocols.