The present proposal has the objective to assess whether the addition of autologous ex vivo expanded mesenchymal stromal cells (XCEL-M-ALPHA) to the conventional meniscal injury rehabilitation program is contributing in creating the proper healing environment for the meniscus repair. For this purpose, 20 patients will be randomized (10 per group) to one of the two treatment arms (rehabilitation + xcel-m-alpha or rehabilitation alone) . The conduction of this clinical trial will, in addition of having the aim of improving the patient's quality of life, contribute to consolidate an emerging new type of therapy which is still under development.