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.

This is a prospective, unicentric, randomized, open-label, single-dose, two-arm, blinded assessor pilot study in which 20 patients with degenerative meniscus injury grade 3 (Crues et al.) will enter the study with the primary objective of assessing the efficacy of the treatment by VAS of pain at 12 month. Secondary objectives are to evaluate the safety and efficacy through imaging procedures and clinical questionnaires (IKDC, KOOS, Lysholm and SF-36.

Patients will be randomized to one of the two treatment arms (XCEL-M-ALPHA and standard rehabilitation program or standard rehabilitation program alone). Thereafter, patients will be followed for 12 months.

Imaging assessment will be performed by an independent blinded radiologist.

Inclusion Criteria:

• Patient between 40 and 60 years of age
• Degenerative meniscus injury grade 3 (Crues et al.)
• Indication of conservative treatment
• Normal alignment of the knee (between 3º varus and 10 º valgus)
• Patient is able to follow a rehabilitation program
• Informed consent given by the patient in writing
• Patient is able to understand the trial.

Exclusion Criteria:

• Traumatic meniscus injury
• Surgical intervention to the affected knee
• Local or systemic infection
• Intraarticular treatment of the affected knee with steroids or hyaluronic acid within the past 3 months
• Significant abnormal laboratory tests that contraindicates participation in the trial.
• Pregnant women or intend to become pregnant or breast-feeding
• Neoplastic process within the previous 5 years or without complete remission.
• The patient is wearing a pacemaker, allergy to contrast, severe renal insufficiency or any other condition that contraindicates the magnetic resonance using contrast.
• Other pathologic conditions or circumstances that difficult participation in the study according to medical criteria
• Legally dependant patient.
• The patient does not accept to be followed-up for a period that could exceed the clinical trial length