Overview
Osteochondritis dissecans (os-tee-o-kohn-DRY-tis DIS-uh-kanz) is a joint condition in which a piece of cartilage, along with a thin layer of the bone beneath it, comes loose from the end of a bone. Caused by reduced blood flow to the end of a bone, osteochondritis dissecans occurs most often in young men, particularly after an injury to a joint. The knee is most commonly affected, although osteochondritis dissecans can occur in other joints, including your elbow, shoulder, hip and ankle.
Causes
Reduction of blood flow the end of the affected bone
Repetitive trauma
Genetics
Symptoms
Pain especially when walking up stairs, climbing a hill, or playing sports
Joint popping or locking
Joint weakness
Decreased range of motion
Swelling and tenderness
Diagnosis
Physical examination and medical history consultation
X-rays
CT scan
MRI
Treatment
Rest
Physical therapy
Surgery
Source: http://www.mayoclinic.com/health/osteochondritis-dissecans/DS00741