Intra Articular Injections With Platelet Rich Plasma in Patients With Juvenile Osteochondritis Dissecans of the Knee

Inclusion Criteria: 1. Male or female age 10 - 17 inclusive with open physis confirmed by MRI 2. Documented symptomatic stable juvenile osteochondritis dissecans of the knee based on MRI without changes of osteoarthritis and no prior history of knee surgery. 3. The patient must be able to hold still without sedation for approximately 1 hour and must pass MRI screening evaluation for retained metal. 4. Patients with Di Paola stage 1 or 2 lesions Exclusion Criteria: 1. Patients with polyarticular disease. 2. Patients with blood disorders (Blood disorders (thrombopathy, thrombocytopenia, anemia with hemoglobin \<9g/dL). Only those patients with a positive history of blood disorders will have a Complete Blood Count (CBC) performed a week prior to inclusion in the study. 3. Patients who had intra-articular treatment with steroids within 3 months 4. Patients who are pregnant or nursing at the time of consent. 5. Patients with inflammatory arthritic conditions (e.g. rheumatoid arthritis) 6. Non-English speaking patients. (Scores used for evaluation have not been validated in Spanish) 7. Patients who had previous knee surgery 8. Additional disabilities in any of the lower limbs that would interfere with any of the clinical assessments. 9. Chronic use of NSAID (defined as taking non-steroidal anti-inflammatory drug) regularly every week for the last 6 months), steroids or chemotherapy drugs 10. Treatment with NSAIDs within 15 days prior to randomization in this study 11. Patients with a BMI over 30. Due to the fact that this study utilizes an injection technique which may be inaccurate in obese subjects. 12. Patients with a prolongation of bleeding time, e.g. those receiving anticoagulant drug therapy 13. Patients with a contraindication to MRI including: patients with cardiac pacemaker or non-approved intracranial vascular clip, and those with orthopedic hardware as the resulting artifact can complicate interpretation 14. Patients with acute or chronic renal failure 15. Patients with a previous anaphylactic reaction to gadolinium enhanced MRI. 16. Patients with Di Paola stage 3 or 4 lesions