Osteochondritis Dissecans (OCD)
(Osteo – Bone, Chondritis – Cartilage, Dissecans – Separation)
This condition is not uncommon among the active paediatric population. The term OCD refers to an area of bone and cartilage most commonly in the knee, but also in the ankle and elbow that loses its blood supply. It is not known exactly why this occurs but there seems to be a genetic predisposition along with factors such as repetitive trauma in the young active patient. Boys seem to be affected more commonly than girls and it is possible the loss of blood supply may be in part due to a sudden big growth spurt where the blood supply cannot keep pace with the growing bone.
An area of OCD has the potential to lead to long term cartilage damage in the knee. When the bone loses its blood supply, the cells in the area die and the bone becomes weak. It is important to have the area assessed with an MRI scan to ensure the bone and cartilage is not at risk of separating from the underlying bone.
In mild cases, the area will heal of its own accord, however sometimes a small surgical operation (drilling) is needed to encourage the blood supply to regrow. If this is not successful or the diagnosis is made too late, then the bone and cartilage can separate from the underlying bone and become a loose body in the knee. If this happens, it is necessary to operate to fix the fragment back down.