The purpose of this clinical study is to evaluate the use of ProChondrix Cryopreserved Osteochondral Allograft to obtain evidence of effectiveness, defined as an improvement in physical function and pain, when used on a symptomatic cartilage defect on the femoral condyle or patella in a mechanically stable knee.

This clinical study will use a multi-center, prospective design, to evaluate ProChondrix CR in approximately 80 patients who are scheduled to undergo treatment of a cartilage defect on the femoral condyle or patella.Patient follow-up will include a period of 60 months after surgery. During this follow-up period, each patient will be evaluated seven (7) times at: 3, 6, 12, 24, 36, 48 and 60 months after surgical intervention.

Inclusion Criteria:

• Patient is ≥18 and ≤ 60 years old at the time of surgery;
• Symptomatic patient presenting with moderate to severe pain in the index knee - unresponsive to conservative treatment (i.e. medication, bracing, physical therapy) and/or previous surgical intervention;
• Radiographically diagnosed, by MRI, or through arthroscopy, to have a cartilage defect on the femoral condyle or patella between ≥ 1 cm2 and ≤ 5 cm2, measured as a rectangle length x width;
• Will be having a marrow stimulation plus ProChondrix CR procedure;
• Has an intact meniscus (maximum of ≤50% resected);
• Have the ability to understand the requirements of the study, to provide written informed consent, and to comply with the study protocol.

Exclusion Criteria:

• Has > 5° of varus or valgus deformity;
• Bipolar articular cartilage involvement (kissing lesions) of the ipsilateral compartment (i.e. > than ICRS Grade 2 on the opposing articular surface);
• Associated damage to the underlying subchondral bone >2 mm requiring osseous repair;
• Requires concomitant ligament repair other than Anterior Cruciate Ligament (ACL) or Medial Patella-Femoral Ligament (MPFL) reconstruction;
• Body Mass Index (BMI)of ≥ 35 kg/m2;
• Active malignancy: undergoing treatment for tumor or boney traumatic injury or a history of any invasive malignancy (except non-melanoma skin cancer), unless the patient has been treated with curative intent and there have been no clinical signs or symptoms of the malignancy for at least 5 years;
• Clinical and/or radiographic disease in the affected joint that includes: osteoarthritis or avascular necrosis, gout or a history of gout or pseudogout, osteochondritis dissecans with significant bone loss;
• Cartilage lesion location such that the implanted graft will not be adequately shouldered;
• Active local microbial infection or a systemic infection, including prior or pending treatment for HIV, syphilis, Hepatitis B or Hepatitis C;
• Currently immunologically suppressed or immunocompromised, or a medical condition requiring radiation, chemotherapy or immunosuppression;
• Unstable cardiovascular, renal, hepatic, endocrine and/or pulmonary disease, cancer or uncontrolled diabetes;
• Has a history of any inflammatory or connective tissue disease, such as, systemic lupus erythematosus (SLE), Addison's disease, Crohn's disease, multiple sclerosis, polychondritis or rheumatoid arthritis;
• Received hyaluronic acid injections into the joint space ≤ 90 days prior to surgery;
• Is a female patient who is pregnant;
• Physically or mentally compromised (i.e. being currently treated for a psychiatric disorder, senile dementia, Alzheimer's disease) in a manner that would compromise his/her ability to participate in the clinical study;
• Has a history of substance abuse (recreational drugs, alcohol) or has been treated in the last 6 months before enrollment for alcohol and/or drug abuse in an in-patient substance abuse program;
• Patients who, in the opinion of the Investigator, would not be able or willing to comply with the protocol;
• Is currently involved in a study of another investigational product for similar purpose or has been in the previous 90 days;
• Has any contraindications for MRI;
• Is a ward of the state, prisoner, or transient.

Skeletally mature patients between the ages of ≥18 and ≤ 60 who have a symptomatic cartilage defect (Grade 3 or 4) on the femoral condyle or patella, in a mechanically stable knee, or is being mechanically stabilized in the same procedure, between ≥ 1 cm2 and ≤ 5 cm2, measured as a rectangle length x width, as confirmed by MRI or arthroscopy.