Knee-osteoarthritis (OA) is a common and disabling problem, that represents a global health issue since none of the current therapies are truly disease modifying. The use of mesenchymal stem cells (MSCs) in OA-preclinical models has been associated with a reduction in cartilage degradation, the attenuation of bone sclerosis and an effective anti-inflammatory response. Investigators have designed a randomized phase I/II placebo controlled trial of UC-MSCs in knee OA. Outcomes will be evaluated at 12 months, comparing monodosis versus double intra-articular injection, re-randomized at 6 months.

Inclusion Criteria:

• Symptomatic Knee OA, Kellgren and Lawrence grade I, II, III on plain Rx films.
• Chondromalacia patella grade I-III on knee MRI. With or without meniscal tear.
• Stable knee and normal clinical exam of involved extremity
• Written informed consent for patients.

Exclusion Criteria:

• Bilateral symptomatic knee OA
• Local or systemic infection.
• Active neoplasia or immunosuppressive state
• Pregnancy or Breastfeeding
• Body Mass Index ≥ 30
• Presence of Pacemaker or Lower extremity metal implant
• Anticoagulant treatment other than aspirin.
• Recent use of oral (previous month) or intra-articular (previous 3 months) corticosteroids
• Concomitant inflammatory joint disease (cristal, connective tissue disease)
• Valgus (>10o) or Varus (>5o) deformity of involved extremity
• Condilar or Tibial plateau Generalized Bone Marrow edema on MRI
• Significant symptomatic hip or spine disease
• Significant abnormality in baseline lab tests