Osteochondritis Dissecans, also known as OCD or OD occurs when a fragment of bone in a joint separates from the rest of the bone because its blood supply was faulty – it was not getting enough blood to keep it alive. Sometimes, the separated fragment of bone stays in place; if it falls into the joint space, however, there will be pain and the joint may not work properly. The joint, usually the knee or elbow becomes inflamed, sore and painful and will ‘give way’- it catches and locks during movement.
Osteochondritis Dissecans can occur in different joints, including the hip and ankle. The knee is most commonly affected. According to health authorities in the UK and USA, OCD more commonly affects males aged between 10 and 20 years who do a lot of sports. OCD is more common among males and females who take part in active sports regularly.
Even though there has been a great deal of research into the causes of OCD, the causes are still pretty much unknown but here are the main 3 reasons for this condition:
• Ischemia – a restriction of blood supply which starves the bone of essential nutrients. The restricted blood supply is usually caused by some problem with blood vessels (vascular problem). The bone undergoes avascular necrosis – deterioration caused by lack of blood supply). Ischemia usually occurs in conjunction with a history of trauma.
• Genes – some studies have shown that the appearance of OCD in several family members may mean that the susceptibility to the condition is inherited. Others, however, argue that it could be more due to family members having similar sporty lifestyles.
• Repeated stress – repeated stress to the bone/joint can significantly increase the risk of developing OCD. Individuals involved in competitive sports are more likely to regularly stress their joints
Conservative measures – such as activity modification or immobilization (rest). The aim of conservative measure is to get the subchondral bone to heal and to prevent future fracture, crater formation or chondral collapse (‘chondral’ means, relating to, or consisting of cartilage).
If the patient has been involved in some sport they will most likely be told to stop for a while. Immobilizing the joint may require a medical device, such as a brace, or even crutches. If there is pain the doctor may recommend an NSAID (non-steroidal anti-inflammatory medication). Children under the age of 16 should not take aspirin. A physical therapist (UK: physiotherapist) may help with stretching and specific exercises.
Children respond to conservative measures much better than adults.
Surgery – may be recommended if conservative measures have not worked.
• Arthroscopic surgery – the surgeon will aim for minimally invasive arthroscopic surgery, which is less painful and has a faster recovery, as well as a much lower risk of complications. The aim of surgery is twofold: 1. To restore normal bloodflow. 2. Get the joint to work normally again. The surgeon makes a small incision, and inserts some long, thin instruments. With these instruments loose fragments of bone can either be removed or reattached. If the cartilage is still attached to the bone, pins or screws can be used to secure it.
• Osteochondral autograft transfer (OATS) – healthy cartilage is used to replace damaged cartilage on the surface of the joint that receives weight-bearing stresses; it is like a cartilage transplant, but the recipient and donor is the same person (the patient).
After surgery the patient will undergo a rehabilitation program. After an initial period of immobilization physical therapy can help regain joint strength and stability.