Inclusion Criteria - Screening Visit:

• Men and women between 18 and 65 years of age at time of treatmentscreening with symptomatic knee pain indicative of articular cartilage defects of the knee with inadequate response to conservative treatment (e.g., analgesics, rest and physical therapy).
• Intact ligaments or sufficiently repaired ligaments such that the target knee is stable at time of procedure.
• Full range of motion of the affected joint (relative to normal knee) defined as : No loss of range of motion of affected limb >5° on extension and >15 ° flexion compared to contralateral knee
• Normally functioning contralateral knee.
• Maximum calculated score of 50 out of possible 100 on the KOOS subdomain of pain scale. (mMinimum rRaw score of 18 out of 36).
• Maximum calculated score of 63 out of possible 100 on the KOOS subdomain of Activities of Daily Living scale. (mMinimum Rraw score of 25 out of 68).
• Subjects who are willing to give voluntary consent to participate in the study, following a full explanation of the nature and purpose of the study, by signing the informed consent form approved by the Institutional Review Board (IRB) prior to all evaluations.
• Life expectancy greater than 5 years.
• Willing and able to perform the study treatments and procedures, able to comply with post-op rehabilitation and sign an Informed Consent and HIPAA authorization.

During Surgery:

At surgery, the screening visit inclusion criteria must again be reviewed and met, along with the following:

• Articular cartilage defect of the medial, lateral or trochlear femoral condyle with a total area of 2.0 - 6.0 cm2 as measured with a graduated probe across the widest portions of the lesion and treatable with one implant
• Defect-grade III or IV according to the ICRS-classification.

Exclusion Criteria:

Subjects will not be considered for participation in the study if any of the following criteria listed below apply or are discovered prior to randomization:

• Severe obesity (BMI > 40).
• Surgery on the contralateral knee within the 6 months prior to the scheduled arthroscopy.
• Intra-articular injections within 1 month of surgery.
• Prior release and excision of scar tissue except isolated lateral release on target knee.
• Prior surgical treatment using mosaicplasty, autologous chondrocyte implantation and/or microfracture on the target knee.
  • Note: prior debridement and lavage are acceptable if more than three months have passed
• Clinically significant low back and/or lower extremity pain not due to the articular cartilage defect.
• Women of child bearing potential must test negative on standard urine pregnancy test and must agree to practice appropriate contraceptive methods for the first 24 months of the study (e. g. oral contraceptive, double barrier method, IUD, intra-muscular contraceptive).
• Clinically significant rheumatological disease (including Lyme, Fibromyalgia) .
• Clinically significant arthritis.
• Radiologically apparent degenerative joint disease as assessed by X-ray within 3 months of screening including joint space narrowing greater than one third when compared to the normal knee or less than 3 mm joint space measured on x-ray (including, but not limited to, weight bearing AP, PA flexed and lateral with magnification spheres; merchant view; hip to ankle alignment images) (in standing views).
• Documented abnormalities of clinically relevant bone integrity or bone healing (including hyperparathyroid and osteoporosis or osteopenia, chronic renal failure or have had previous fragility fractures unless there is a documented Dexa T-score of >-1 within the past 3 months).
• Bone diseases including but not limited to Paget’s Disease.
• Immune suppression (including CD4 values under 200; and/or chemotherapy).
• Immune modulating drugs such as immunosuppressants (ex. Imuran;) phosphonates; antimetabolites (ex. methotrexate), Gabapentin (neurontin) and Pregabaline (ex Lyrica).
• Current steroid (anabolic or corticosteroid) use or steroid use within the last 3 months prior to screening.
• Autoimmune disease (including Lupus, ankylosing spondylitis or sero negative arthropathy).
• Connective tissue or collagen disease including but not limited to Ehler-Danlos.
• Any degenerative muscular, connective tissue or neurological condition or other disease process that would interfere healing or the evaluation of outcome measures including but not limited to Parkinson’s disease, acute lateral sclerosis, multiple sclerosis.
• Current diagnosis or treatment for any infectious diseases at time of surgery.
• Clinically relevant vascular disorders including but not limited to peripheral vascular disease or peripheral artery disease.
• Subjects currently taking anti-coagulants (i.e., Plavix).
• Current uncontrolled diabetes.
• History of deep vein thrombosis and pulmonary embolism.
• Documented coagulation disorders or thromboembolic disease.
• Any currently active diagnosis of endocrine disorder without satisfactory treatment (ie hyperthyroidism without stable treatment).
• Human growth hormone medications.
• Primary synovial neoplasm.
• Previous malignancy in the bones, cartilage, fat or muscle of the treated limb; or any other location within the past 3 years (except non-melanoma skin cancer) .
• Currently participating, or have participated in any other clinical trial within 3 months prior to the Screening Visit.
• Psychiatric or cognitive impairment, that in the opinion of the investigator, would interfere with the subject’s ability to comply with the study requirements or measurements( e.g., Alzheimer’s Disease).
• Known current or recent history of illicit drug or alcohol abuse (including steroid use), or dependence defined as the continued use of alcohol/drugs despite the development of social, legal or health problems.
• Unable to undergo magnetic resonance imaging (MRI).
• Sensitivity to bovine materials; or history of host reaction/rejection.
• Subjects receiving ongoing Workman’s Compensation or other liability injury claim.