Osteochondritis dissecans (OCD) is a condition that occurs in young people and most frequently occurs in the knee. OCD results from a separation of a part of the lining of the knee joint (hyaline cartilage) from the underlying bone. This causes cracking and loosening of the lining of the knee joint. Many cases of OCD in the knee heal spontaneously. However, some patients have ongoing symptoms and may require operative treatment.
OCD in the knee is usually seen in the lower part of the femur (femoral condyle). The cause of OCD is not clearly understood, however, it is thought to relate to a deficiency of the blood supply to the lining of the knee.
OCD of the knee can cause pain and swelling, particularly with sporting activities. If OCD progresses, then there can be catching or locking of the knee joint especially if a part of the lining of the knee becomes loose.
The diagnosis of OCD of the knee is made by taking a thorough history and performing a physical examination. X-rays will confirm the diagnosis. Often an MRI scan gives more information to assist in the management of this condition.
The treatment of OCD depends on the size of the lesion in the knee and its stability. Most lesions in children and teenagers heal spontaneously. Sport may need to be curtailed if pain and swelling symptoms persist. Crutches may be helpful in the short term to allow an OCD lesion in the knee to heal. Physiotherapy is useful to maintain strength in the affected leg.
If an OCD lesion becomes unstable or loose, then surgery may be necessary. This may include knee arthroscopy during which the unstable fragment is fixed with special dissolving screws or the fragment is removed. If the defect in the bone and cartilage is large then cartilage grafting may be required.