This study is to compare NOVOCART 3D relative to Microfracture for the treatment of knee cartilage defects. Efficacy will be evaluated by both pain and function. Safety will also be evaluated.

Subjects with articular knee defects will be randomized to receive either Microfracture or NOVOCART 3D. Subjects will be followed for five years in total and will be evaluated for safety and efficacy.

Inclusion Criteria:

• Greater than 18 years old
• Isolated articular cartilage lesions on the femoral condyle 2-6 cm2
• Minimum score on the KOOS questionnaire

Exclusion Criteria:

• Instability of the knee joint
• Arthritis
• Autoimmune disease
• Immune suppression
• Prior surgical treatment using mosaicplasty, autologous chondrocyte implantation and/or microfracture (debridement and lavage are acceptable beyond three months from baseline)
• Bone disease
• Any degenerative muscular, connective tissue or neurological condition or other disease process that would interfere with healing or the evaluation of outcome measures.